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Cisco IOS IP Addressing Services Command Reference
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Introduction
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ARP Commands
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DHCP Commands: accounting (DHCP) through ip dhcp excluded-address
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DHCP Commands: ip dhcp limit lease through lease
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DHCP Commands: netbios-name-server through vrf (DHCP pool)
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DNS Commands: ddns (DDNS-update-method) through ip dns server queue limit
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DNS Commands: ip dns spoofing through view (DNS)
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IP Addressing Commands
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NAT Commands
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NHRP Commands
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Table Of Contents
ip verify source vlan dhcp-snooping
local-ip (IPC transport-SCTP local)
remote-ip (IPC transport-SCTP remote)
IP Addressing Commands
clear host
To delete hostname-to-address mapping entries from one or more hostname caches, use the clear host command in privileged EXEC mode.
clear host [view view-name | vrf vrf-name | all] {hostname | *}
Syntax Description
Command Default
No hostname-to-address mapping entries are deleted from any hostname cache.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
This command clears the specified hostname cache entries in running memory, but it does not remove the entries from NVRAM.
Entries can be removed from the hostname caches for a DNS view name, from the hostname caches for a VRF, or from all configured hostname caches. To remove entries from hostname caches for a particular DNS view name, use the view keyword and view-name argument. To remove entries from the hostname caches for a particular VRF, use the vrf keyword and vrf-name argument. To remove entries from all configured hostname caches, use the all keyword.
To remove entries that provide mapping information for a single hostname, use the hostname argument. To remove all entries, use the * keyword.
To display the cached list of hostnames and addresses specific to a particular DNS view or for all configured DNS views, use the show hosts command.
To define static hostname-to-address mappings in the DNS hostname cache for a DNS view, use the ip host command.
Examples
The following example shows how to clear all entries from the hostname cache for the default view in the global address space:
Router# clear host all *The following example shows how to clear entries for the hostname www.example.com from the hostname cache for the default view associated with the VPN named vpn101:
Router# clear host vrf vpn101 www.example.comThe following example shows how to clear all entries from the hostname cache for the view named user2 in the global address space:
Router# clear host view user2 *Related Commands
clear ip route
To delete routes from the IP routing table, use the clear ip route command in EXEC mode.
clear ip route {network [mask] | *}
Syntax Description
network
Network or subnet address to remove.
mask
(Optional) Subnet address to remove.
*
Removes all routing table entries.
Defaults
All entries are removed.
Command Modes
EXEC
Command History
Examples
The following example removes a route to network 10.5.0.0 from the IP routing table:
Router> clear ip route 10.5.0.0ip address
To set a primary or secondary IP address for an interface, use the ip address command in interface configuration mode. To remove an IP address or disable IP processing, use the no form of this command.
ip address ip-address mask [secondary [vrf vrf-name]]
no ip address ip-address mask [secondary [vrf vrf-name]]
Syntax Description
Command Default
No IP address is defined for the interface.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
An interface can have one primary IP address and multiple secondary IP addresses. Packets generated by the Cisco IOS software always use the primary IP address. Therefore, all routers and access servers on a segment should share the same primary network number.
Hosts can determine subnet masks using the Internet Control Message Protocol (ICMP) mask request message. Routers respond to this request with an ICMP mask reply message.
You can disable IP processing on a particular interface by removing its IP address with the no ip address command. If the software detects another host using one of its IP addresses, it will print an error message on the console.
The optional secondary keyword allows you to specify an unlimited number of secondary addresses. Secondary addresses are treated like primary addresses, except the system never generates datagrams other than routing updates with secondary source addresses. IP broadcasts and Address Resolution Protocol (ARP) requests are handled properly, as are interface routes in the IP routing table.
Secondary IP addresses can be used in a variety of situations. The following are the most common applications:
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There may not be enough host addresses for a particular network segment. For example, your subnetting allows up to 254 hosts per logical subnet, but on one physical subnet you need 300 host addresses. Using secondary IP addresses on the routers or access servers allows you to have two logical subnets using one physical subnet.
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Note
Note
To transparently bridge IP on an interface, you must perform the following two tasks:
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To concurrently route and transparently bridge IP on an interface, see the bridge crb command.
Examples
In the following example, 192.108.1.27 is the primary address and 192.31.7.17 and 192.31.8.17 are secondary addresses for Ethernet interface 0:
interface ethernet 0ip address 192.108.1.27 255.255.255.0ip address 192.31.7.17 255.255.255.0 secondaryip address 192.31.8.17 255.255.255.0 secondaryIn the following example, Ethernet interface 0/1 is configured to automatically classify the source IP address in the VRF table vrf1:
interface ethernet 0/1ip address 10.108.1.27 255.255.255.0ip address 10.31.7.17 255.255.255.0 secondary vrf vrf1ip vrf autoclassify sourceRelated Commands
ip classless
To enable a router to forward packets, which are destined for a subnet of a network that has no network default route, to the best supernet route possible, use the ip classless command in global configuration mode. To disable the functionality, use the no form of this command.
ip classless
no ip classless
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Global configuration
Command History
Usage Guidelines
This command allows the software to forward packets that are destined for unrecognized subnets of directly connected networks. The packets are forwarded to the best supernet route.
When this feature is disabled, the Cisco IOS software discards the packets when a router receives packets for a subnet that numerically falls within its subnetwork addressing scheme, no such subnet number is in the routing table, and there is no network default route.
Note
Examples
The following example prevents the software from forwarding packets destined for an unrecognized subnet to the best supernet possible:
no ip classlessip default-gateway
To define a default gateway (router) when IP routing is disabled, use the ip default-gateway command in global configuration mode. To disable this function, use the no form of this command.
ip default-gateway ip-address
no ip default-gateway ip-address
Syntax Description
Defaults
Disabled
Command Modes
Global configuration
Command History
Usage Guidelines
The Cisco IOS software sends any packets that need the assistance of a gateway to the address you specify. If another gateway has a better route to the requested host, the default gateway sends an Internet Control Message Protocol (ICMP) redirect message back. The ICMP redirect message indicates which local router the Cisco IOS software should use.
Examples
The following example defines the router on IP address 192.31.7.18 as the default router:
ip default-gateway 192.31.7.18Related Commands
ip host
To define static hostname-to-address mappings in the Domain Name System (DNS) hostname cache for a DNS view, use the ip host command in global configuration mode. If the hostname cache does not exist yet, it is automatically created. To remove a hostname-to-address mapping, use the no form of this command.
ip host [vrf vrf-name] [view view-name] {hostname | tmodem-telephone-number} [tcp-port-number] {ip-address1 [ip-address2...ip-address8] | additional ip-address9 [ip-address10...ip-addressn] | [mx preference mx-server-hostname | ns nameserver-hostname | srv priority weight port target]}
no ip host [vrf vrf-name] [view view-name] {hostname | tmodem-telephone-number} [tcp-port-number] {ip-address1 [ip-address2...ip-address8] additional ip-address9 [ip-address10...ip-addressn] | [mx preference mx-server-hostname | ns nameserver-hostname | srv priority weight port target]}
Syntax Description
Command Default
No static hostname-to-address mapping is added to the DNS hostname cache for a DNS view.
Command Modes
Global configuration
Command History
Usage Guidelines
This command adds the specified hostname-to-IP address mappings as follows:
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If the specified VRF does not exist yet, a warning is displayed and the entry is added to the hostname cache anyway.
If the specified view does not exist yet, a warning is displayed and the entry is added to the hostname cache anyway.
If the hostname cache does not exist yet, it is automatically created.
To specify the machine that provides domain service for the domain, use the ns keyword and the nameserver-hostname argument
To specify where the mail for the host is to be sent, use the mx keyword and the preference and mx-server-hostname arguments.
To specify a host that offers a service in the domain, use thhe srv keyword and the priority, weight, port, and target arguments.
To display the display the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses specific to a particular DNS view or for all configured DNS views, use the show hosts command.
Note
Examples
The following example shows how to add three mapping entries to the global hostname cache and then remove one of those entries from the global hostname cache:
Router(config)# ip host www.example1.com 192.0.2.141 192.0.2.241Router(config)# ip host www.example2.com 192.0.2.242Router(config)# no ip host www.example1.com 192.0.2.141The following example shows how to add three mapping entries to the hostname cache for the DNS view user3 that is associated with the VRF vpn101 and then remove one of those entries from that hostname cache:
Router(config)# ip host vrf vpn101 view user3 www.example1.com 192.0.2.141 192.0.2.241Router(config)# ip host vrf vpn101 view user3 www.example2.com 192.0.2.242Router(config)# no ip host vrf vpn101 view user3 www.example1.com 192.0.2.141Related Commands
ip hostname strict
To ensure that Internet hostnames comply with Section 2.1 of RFC 1123, use the ip hostname strict command in global configuration mode. To remove the restriction on hostnames, use the no form of this command.
ip hostname strict
no ip hostname strict
Syntax Description
This command has no arguments or keywords.
Command Default
This command is disabled by default, that is, characters that are not specified in Section 2.1 of RFC 1123 are allowed in hostnames.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Section 2.1 of RFC 1123 specifies the following rules for hostnames:
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The following hostnames comply with Section 2.1 of RFC 1123:
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The following hostnames do not comply with Section 2.1 of RFC 1123:
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When the ip hostname strict command is configured on a router, any hostname configured on the router must comply with Section 2.1 of RFC 1123, including the following configurations:
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When the ip hostname strict command is not configured on a router, characters that are not specified in Section 2.1 of RFC 1123 are allowed in hostnames.
Examples
The following example shows how to specify compliance with Section 2.1 of RFC 1123 for hostnames.
Router(config)# ip hostname strictRelated Commands
ip hp-host
To enter into the host table the host name of a Hewlett-Packard (HP) host to be used for HP Probe Proxy service, use the ip hp-host global configuration command. To remove a host name, use the no form of this command.
ip hp-host host-name ip-address
no ip hp-host host-name ip-address
Syntax Description
Defaults
No host names are defined.
Command Modes
Global configuration
Command History
Usage Guidelines
To use the HP Probe Proxy service, you must first enter the host name of the HP host into the host table using this command.
Examples
The following example specifies the name and address of an HP host, and then enables HP Probe Proxy:
ip hp-host BCWjo 131.108.1.27interface fastethernet 0ip probe proxyRelated Commands
ip probe proxy
Enables the HP Probe Proxy support, which allows the Cisco IOS software to respond to HP Probe Proxy name requests.
ip mobile arp
To enable local-area mobility, use the ip mobile arp command in interface configuration mode. To disable local-area mobility, use the no form of this command.
ip mobile arp [timers keepalive hold-time] [access-group access-list-number | name]
no ip mobile arp [timers keepalive hold-time] [access-group access-list-number | name]
Syntax Description
Defaults
Local-area mobility is disabled.
If you enable local-area mobility:
keepalive: 5 minutes (300 seconds)
hold-time: 15 minutes (900 seconds)Command Modes
Interface configuration
Command History
Usage Guidelines
Local-area mobility is supported on Ethernet, Token Ring, and FDDI interfaces only.
To create larger mobility areas, you must first redistribute the mobile routes into your Interior Gateway Protocol (IGP). The IGP must support host routes. You can use Enhanced IGRP, Open Shortest Path First (OSPF), or Intermediate System-to-Intermediate System (IS-IS); you can also use Routing Information Protocol (RIP), but RIP is not recommended. The mobile area must consist of a contiguous set of subnets.
Using an access list to control the list of possible mobile nodes is strongly encouraged. Without an access list, misconfigured hosts can be taken for mobile nodes and disrupt normal operations.
Examples
The following example configures local-area mobility on Ethernet interface 0:
access-list 10 permit 10.92.37.114interface fastethernet 0ip mobile arp access-group 10Related Commands
ip netmask-format
To specify the format in which netmasks are displayed in show command output, use the ip netmask-format command in line configuration mode. To restore the default display format, use the no form of this command.
ip netmask-format {bit-count | decimal | hexadecimal}
no ip netmask-format {bit-count | decimal | hexadecimal}
Syntax Description
Defaults
Netmasks are displayed in dotted-decimal format.
Command Modes
Line configuration
Command History
Usage Guidelines
IP uses a 32-bit mask that indicates which address bits belong to the network and subnetwork fields, and which bits belong to the host field. This is called a netmask. By default, show commands display an IP address and then its netmask in dotted decimal notation. For example, a subnet would be displayed as 10.108.11.0 255.255.255.0.
However, you can specify that the display of the network mask appear in hexadecimal format or bit count format instead. The hexadecimal format is commonly used on UNIX systems. The previous example would be displayed as 10.108.11.0 0XFFFFFF00.
The bitcount format for displaying network masks is to append a slash (/) and the total number of bits in the netmask to the address itself. The previous example would be displayed as 10.108.11.0/24.
Examples
The following example configures network masks for the specified line to be displayed in bitcount notation in the output of show commands:
line vty 0 4ip netmask-format bitcountip options
To drop or ignore IP options packets that are sent to the router, use the ip options command in global configuration mode. To disable this functionality and allow all IP options packets to be sent to the router, use the no form of this command.
ip options {drop | ignore}
no ip options {drop | ignore}
Syntax Description
Defaults
This command is not enabled.
Command Modes
Global configuration
Command History
Usage Guidelines
The ip options command allows you to filter IP options packets, mitigating the effects of IP options on the router, and on downstream routers and hosts.
Drop and ignore modes are mutually exclusive; that is, if the drop mode is configured and you configure the ignore mode, the ignore mode overrides the drop mode.
Cisco 10720 Internet Router
The ip options ignore command is not supported. Only drop mode (the ip options drop command) is supported.
Cisco 10000 Series Router
This command is only available on the PRE3. The PRE2 does not support this command.
The ip options ignore command is not supported. The router supports only the ip options drop command.
Examples
The following example shows how to configure the router (and downstream routers) to drop all options packets that enter the network:
ip options drop% Warning:RSVP and other protocols that use IP Options packets may not function in drop or ignore modes.endip probe proxy
To enable the HP Probe Proxy support, which allows the Cisco IOS software to respond to HP Probe Proxy name requests, use the ip probe proxy interface configuration command. To disable HP Probe Proxy, use the no form of this command.
ip probe proxy
no ip probe proxy
Syntax Description
This command has no arguments or keywords.
Defaults
Disabled
Command Modes
Interface configuration
Command History
Usage Guidelines
HP Probe Proxy Name requests are typically used at sites that have Hewlett-Packard (HP) equipment and are already using HP Probe.
To use the HP Probe Proxy service, you must first enter the host name of the HP host into the host table using the ip hp-host global configuration command.
Examples
The following example specifies an HP host name and address, and then enables Probe Proxy:
ip hp-host BCWjo 131.108.1.27interface fastethernet 0ip probe proxyRelated Commands
ip hp-host
Enters into the host table the host name of an HP host to be used for HP Probe Proxy service.
ip route
To establish static routes, use the ip route command in global configuration mode. To remove static routes, use the no form of this command.
ip route [vrf vrf-name] prefix mask {ip-address | interface-type interface-number [ip-address]} [dhcp] [distance] [name next-hop-name] [permanent | track number] [tag tag]
no ip route [vrf vrf-name] prefix mask {ip-address | interface-type interface-number [ip-address]} [dhcp] [distance] [name next-hop-name] [permanent | track number] [tag tag]
Syntax Description
Command Default
No static routes are established.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
The establishment of a static route is appropriate when the Cisco IOS software cannot dynamically build a route to the destination.
When you specify a DHCP server to assign a static route, the interface type and number and administrative distance may be configured also.
If you specify an administrative distance, you are flagging a static route that can be overridden by dynamic information. For example, routes derived with Enhanced Interior Gateway Routing Protocol (EIGRP) have a default administrative distance of 100. To have a static route that would be overridden by an EIGRP dynamic route, specify an administrative distance greater than 100. Static routes have a default administrative distance of 1.
Static routes that point to an interface on a connected router will be advertised by way of Routing Information Protocol (RIP) and EIGRP regardless of whether redistribute static commands are specified for those routing protocols. This situation occurs because static routes that point to an interface are considered in the routing table to be connected and hence lose their static nature. Also, the target of the static route should be included in the network (DHCP) command. If this condition is not met, no dynamic routing protocol will advertise the route unless a redistribute static command is specified for these protocols. With the following configuration:
rtr1 (serial 172.16.188.1/30)--------------> rtr2(Fast Ethernet 172.31.1.1/30) ------>router [rip | eigrp]network 172.16.188.0network 172.31.0.0•
ip route 172.16.188.252 255.255.255.252 FastEthernet 0/0RIP and EIGRP do not redistribute the route with the following ip route command because of the split horizon algorithm:
ip route 172.16.188.252 255.255.255.252 serial 2/1•
ip route 172.16.188.252 255.255.255.252 FastEthernet 0/0ip route 172.16.188.252 255.255.255.252 serial 2/1With the Open Shortest Path First (OSPF) protocol, static routes that point to an interface are not advertised unless a redistribute static command is specified.
Adding a static route to an Ethernet or other broadcast interface (for example, ip route 0.0.0.0 0.0.0.0 Ethernet 1/2) will cause the route to be inserted into the routing table only when the interface is up. This configuration is not generally recommended. When the next hop of a static route points to an interface, the router considers each of the hosts within the range of the route to be directly connected through that interface, and therefore it will send Address Resolution Protocol (ARP) requests to any destination addresses that route through the static route.
A logical outgoing interface, for example, a tunnel, needs to be configured for a static route. If this outgoing interface is deleted from the configuration, the static route is removed from the configuration and hence does not show up in the routing table. To have the static route inserted into the routing table again, configure the outgoing interface once again and add the static route to this interface.
The practical implication of configuring the ip route 0.0.0.0 0.0.0.0 ethernet 1/2 command is that the router will consider all of the destinations that the router does not know how to reach through some other route as directly connected to Ethernet interface 1/2. So the router will send an ARP request for each host for which it receives packets on this network segment. This configuration can cause high processor utilization and a large ARP cache (along with memory allocation failures). Configuring a default route or other static route that directs the router to forward packets for a large range of destinations to a connected broadcast network segment can cause your router to reload.
Specifying a numerical next hop that is on a directly connected interface will prevent the router from using proxy ARP. However, if the interface with the next hop goes down and the numerical next hop can be reached through a recursive route, you may specify both the next hop and interface (for example, ip route 0.0.0.0 0.0.0.0 ethernet 1/2 10.1.2.3) with a static route to prevent routes from passing through an unintended interface.
Note
The name next-hop-name keyword and argument combination allows you to associate static routes with names in your running configuration. If you have several static routes, you can specify names that describe the purpose of each static route in order to more easily identify each one.
The track number keyword and argument combination specifies that the static route will be installed only if the state of the configured track object is up.
Recursive Static Routing
In a recursive static route, only the next hop is specified. The output interface is derived from the next hop.
For the following recursive static route example, all destinations with the IP address prefix address prefix 192.168.1.1/32 are reachable via the host with address 10.0.0.2:
ip route 192.168.1.1 255.255.255.255 10.0.0.2
A recursive static route is valid (that is, it is a candidate for insertion in the IPv4 routing table) only when the specified next hop resolves, either directly or indirectly, to a valid IPv4 output interface, provided the route does not self-recurse, and the recursion depth does not exceed the maximum IPv4 forwarding recursion depth.
The following example defines a valid recursive IPv4 static route:
interface serial 2/0ip address 10.0.0.1 255.255.255.252exitip route 192.168.1.1 255.255.255.255 10.0.0.2The following example defines an invalid recursive IPv4 static route. This static route will not be inserted into the IPv4 routing table because it is self-recursive. The next hop of the static route, 192.168.1.0/30, resolves via the first static route 192.168.1.0/24, which is itself a recursive route (that is, it only specifies a next hop). The next hop of the first route, 192.168.1.0/24, resolves via the directly connected route via the serial interface 2/0. Therefore, the first static route would be used to resolve its own next hop.
interface serial 2/0ip address 10.0.0.1 255.255.255.252exitip route 192.168.1.0 255.255.255.0 10.0.0.2ip route 192.168.1.0 255.255.255.252 192.168.1.100It is not normally useful to manually configure a self-recursive static route, although it is not prohibited. However, a recursive static route that has been inserted in the IPv4 routing table may become self-recursive as a result of some transient change in the network learned through a dynamic routing protocol. If this situation occurs, the fact that the static route has become self-recursive will be detected and the static route will be removed from the IPv4 routing table, although not from the configuration. A subsequent network change may cause the static route to no longer be self-recursive, in which case it will be re-inserted in the IPv4 routing table.
Note
Examples
The following example shows how to choose an administrative distance of 110. In this case, packets for network 10.0.0.0 will be routed to a router at 172.31.3.4 if dynamic information with an administrative distance less than 110 is not available.
ip route 10.0.0.0 255.0.0.0 172.31.3.4 110
Note
The following example shows how to route packets for network 172.31.0.0 to a router at 172.31.6.6:
ip route 172.31.0.0 255.255.0.0 172.31.6.6The following example shows how to route packets for network 192.168.1.0 directly to the next hop at 10.1.2.3. If the interface goes down, this route is removed from the routing table and will not be restored unless the interface comes back up.
ip route 192.168.1.0 255.255.255.0 Ethernet 0 10.1.2.3The following example shows how to install the static route only if the state of track object 123 is up:
ip route 0.0.0.0 0.0.0.0 Ethernet 0/1 10.1.1.242 track 123The following example shows that using the dhcp keyword in a configuration of Ethernet interfaces 1 and 2 enables the interfaces to obtain the next-hop router IP addresses dynamically from a DHCP server:
ip route 10.165.200.225 255.255.255.255 ethernet1 dhcpip route 10.165.200.226 255.255.255.255 ethernet2 dhcp 20The following example shows that using the name next-hop-name keyword and argument combination for each static route in the configuration helps you remember the purpose for each static route.
ip route 172.0.0.0 255.0.0.0 10.0.0.1 name Seattle2DetroitThe name for the static route will be displayed when the show running-configuration command is entered:
Router# show running-config | include ip routeip route 172.0.0.0 255.0.0.0 10.0.0.1 name Seattle2DetroitRelated Commands
ip route vrf
To establish static routes for a Virtual Private Network (VPN) routing and forwarding (VRF) instance, use the ip route vrf command in global configuration mode. To disable static routes, use the no form of this command.
ip route vrf vrf-name prefix mask [next-hop-address] [interface interface-number] [global] [distance] [permanent] [tag tag]
no ip route vrf vrf-name prefix mask [next-hop-address] [interface interface-number] [global] [distance] [permanent] [tag tag]
Syntax Description
Defaults
No default behavior or values.
Command Modes
Global configuration
Command History
Usage Guidelines
Use a static route when the Cisco IOS software cannot dynamically build a route to the destination.
If you specify an administrative distance when you set up a route, you are flagging a static route that can be overridden by dynamic information. For example, Interior Gateway Routing Protocol (IGRP)-derived routes have a default administrative distance of 100. To set a static route to be overridden by an IGRP dynamic route, specify an administrative distance greater than 100. Static routes each have a default administrative distance of 1.
Static routes that point to an interface are advertised through the Routing Information Protocol (RIP), IGRP, and other dynamic routing protocols, regardless of whether the routes are redistributed into those routing protocols. That is, static routes configured by specifying an interface lose their static nature when installed into the routing table.
However, if you define a static route to an interface not defined in a network command, no dynamic routing protocols advertise the route unless a redistribute static command is specified for these protocols.
Supported Static Route Configurations
When you configure static routes in a Multiprotocol Label Switching (MPLS) or MPLS VPN environment, note that some variations of the ip route and ip route vrf commands are not supported. These variations of the commands are not supported in Cisco IOS releases that support the Tag Forwarding Information Base (TFIB), specifically Cisco IOS releases 12.xT, 12.xM, and 12.0S. The TFIB cannot resolve prefixes when the recursive route over which the prefixes travel disappears and then reappears. However, the command variations are supported in Cisco IOS releases that support the MPLS Forwarding Infrastructure (MFI), specifically Cisco IOS release 12.2(25)S and later releases. Use the following guidelines when configuring static routes.
Supported Static Routes in an MPLS Environment
The following ip route command is supported when you configure static routes in an MPLS environment:
ip route destination-prefix mask interface next-hop-address
The following ip route commands are supported when you configure static routes in an MPLS environment and configure load sharing with static nonrecursive routes and a specific outbound interface:
ip route destination-prefix mask interface1 next-hop1
ip route destination-prefix mask interface2 next-hop2Unsupported Static Routes in an MPLS Environment That Uses the TFIB
The following ip route command is not supported when you configure static routes in an MPLS environment:
ip route destination-prefix mask next-hop-address
The following ip route command is not supported when you configure static routes in an MPLS environment and enable load sharing where the next hop can be reached through two paths:
ip route destination-prefix mask next-hop-address
The following ip route command is not supported when you configure static routes in an MPLS environment and enable load sharing where the destination can be reached through two next hops:
ip route destination-prefix mask next-hop1
ip route destination-prefix mask next-hop2Use the interface and next-hop arguments when specifying static routes.
Supported Static Routes in an MPLS VPN Environment
The following ip route vrf commands are supported when you configure static routes in an MPLS VPN environment, and the next hop and interface are in the same VRF:
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ip route vrf vrf-name destination-prefix mask interface2 next-hop2The following ip route vrf commands are supported when you configure static routes in an MPLS VPN environment, and the next hop is in the global table in the MPLS cloud in the global routing table. For example, these commands are supported when the next hop is pointing to the Internet gateway.
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(This command is supported when the next hop and interface are in the core.)The following ip route commands are supported when you configure static routes in an MPLS VPN environment and enable load sharing with static nonrecursive routes and a specific outbound interface:
ip route destination-prefix mask interface1 next-hop1
ip route destination-prefix mask interface2 next-hop2Unsupported Static Routes in an MPLS VPN Environment That Uses the TFIB
The following ip route command is not supported when you configure static routes in an MPLS VPN environment, the next hop is in the global table in the MPLS cloud within the core, and you enable load sharing where the next hop can be reached through two paths:
ip route vrf destination-prefix mask next-hop-address global
The following ip route commands are not supported when you configure static routes in an MPLS VPN environment, the next hop is in the global table in the MPLS cloud within the core, and you enable load sharing where the destination can be reached through two next hops:
ip route vrf destination-prefix mask next-hop1 global
ip route vrf destination-prefix mask next-hop2 globalThe following ip route vrf commands are not supported when you configure static routes in an MPLS VPN environment, and the next hop and interface are in the same VRF:
ip route vrf vrf-name destination-prefix mask next-hop1
ip route vrf vrf-name destination-prefix mask next-hop2Supported Static Routes in an MPLS VPN Environment Where the Next Hop Resides in the Global Table on the CE Router
The following ip route vrf command is supported when you configure static routes in an MPLS VPN environment, and the next hop is in the global table on the customer equipment (CE) side. For example, the following command is supported when the destination prefix is the CE router's loopback address, as in external BGP (EBGP) multihop cases.
ip route vrf vrf-name destination-prefix mask interface next-hop-address
The following ip route commands are supported when you configure static routes in an MPLS VPN environment, the next hop is in the global table on the CE side, and you enable load sharing with static nonrecursive routes and a specific outbound interfaces:
ip route destination-prefix mask interface1 nexthop1
ip route destination-prefix mask interface2 nexthop2Examples
The following command shows how to reroute packets addressed to network 10.23.0.0 in VRF vpn3 to router 10.31.6.6:
Router(config)# ip route vrf vpn3 10.23.0.0 255.255.0.0 10.31.6.6Related Commands
show ip route vrf
Displays the IP routing table associated with a VRF.
redistribute static
Redistributes routes from another routing domain into the specified domain.
ip routing
To enable IP routing, use the ip routing command in global configuration mode. To disable IP routing, use the no form of this command.
ip routing
no ip routing
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Global configuration
Command History
Usage Guidelines
To bridge IP, the no ip routing command must be configured to disable IP routing. However, you need not specify no ip routing in conjunction with concurrent routing and bridging to bridge IP.
The ip routing command is disabled on the Cisco VG200 voice over IP gateway.
Examples
The following example enables IP routing:
ip routingip source binding
To add a static IP source binding entry, use the ip source binding command. Use the no form of this command to delete a static IP source binding entry
ip source binding mac-address vlan vlan-id ip-address interface type mod/port
Syntax Description
Command Default
No IP source bindings are configured.
Command Modes
Global configuration.
Command History
Usage Guidelines
You can use this command to add a static IP source binding entry only.
The no format deletes the corresponding IP source binding entry. It requires the exact match of all required parameter in order for the deletion to be successful. Note that each static IP binding entry is keyed by a MAC address and a VLAN number. If the command contains the existing MAC address and VLAN number, the existing binding entry is updated with the new parameters instead of creating a separate binding entry.
Examples
This example shows how to add a static IP source binding entry:
Router(config)# ip source binding 000C.0203.0405 vlan 100 172.16.30.2 interface gigabitethernet5/3This example shows how to delete a static IP source binding entry:
Router(config)# no ip source binding 000C.0203.0405 vlan 100 172.16.30.2 interface gigabitethernet5/3Related Commands
ip source-route
To allow the Cisco IOS software to handle IP datagrams with source routing header options, use the ip source-route command in global configuration mode. To have the software discard any IP datagram containing a source-route option, use the no form of this command.
ip source-route
no ip source-route
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Global configuration
Command History
Examples
The following example enables the handling of IP datagrams with source routing header options:
ip source-routeRelated Commands
ip subnet-zero
To enable the use of subnet 0 for interface addresses and routing updates, use the ip subnet-zero command in global configuration mode. To restore the default, use the no form of this command.
ip subnet-zero
no ip subnet-zero
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Global configuration
Command History
Usage Guidelines
The ip subnet-zero command provides the ability to configure and route to subnet 0 subnets.
Subnetting with a subnet address of 0 is discouraged because of the confusion inherent in having a network and a subnet with indistinguishable addresses.
Examples
The following example enables subnet zero:
ip subnet-zeroip unnumbered
To enable IP processing on an interface without assigning an explicit IP address to the interface, use the ip unnumbered command in interface configuration mode or subinterface configuration mode. To disable the IP processing on the interface, use the no form of this command.
ip unnumbered type number
no ip unnumbered type number
Syntax Description
Command Default
IP processing on the unnumbered interface is disabled.
Command Modes
Interface configuration
Subinterface configurationCommand History
Usage Guidelines
When an unnumbered interface generates a packet (for example, for a routing update), it uses the address of the specified interface as the source address of the IP packet. It also uses the address of the specified interface in determining which routing processes are sending updates over the unnumbered interface. Restrictions are as follows:
•
•
•
•
•
The interface you specify by the type and `number arguments must be enabled (listed as "up" in the show interfaces command display).
If you are configuring Intermediate System-to-Intermediate System (IS-IS) across a serial line, you should configure the serial interfaces as unnumbered. This configuration allows you to comply with RFC 1195, which states that IP addresses are not required on each interface.
Note
Examples
In the following example, the first serial interface is given the address of Ethernet 0:
interface fastethernet 0ip address 10.108.6.6 255.255.255.0!interface serial 0ip unnumbered fastethernet 0In the following example, Ethernet VLAN subinterface 3/0.2 is configured as an IP unnumbered subinterface:
interface fastethernet 3/0.2encapsulation dot1q 200ip unnumbered fastethernet 3/1In the following example, Fast Ethernet subinterfaces in the range from 5/1.1 to 5/1.4 are configured as IP unnumbered subinterfaces:
interface range fastethernet5/1.1 - fastethernet5/1.4ip unnumbered fastethernet 3/1ip verify source vlan dhcp-snooping
To enable Layer 2 IP source guard, use the ip verify source vlan dhcp-snooping command in the service instance mode. Use the no form of this command to disable Layer 2 IP source guard.
ip verify source vlan dhcp-snooping [port-security]
no ip verify source vlan dhcp-snooping [port-security]
Syntax Description
Command Default
Layer 2 IP source guard is disabled.
Command Modes
Service instance (config-if-srv)
Command History
12.2(33)SXH
This command was introduced.
12.2(33)SRD
The port-security keyword was added.
Usage Guidelines
The ip verify source vlan dhcp-snooping command enables VLANs only on the configured service instance (EVC) and looks for DHCP snooping matches only for the configured bridge domain VLAN.
Examples
This example shows how to enable Layer 2 IP source guard on an interface:
Router# enableRouter# configure terminalRouter(config)# interface GigabitEthernet7/1Router(config-if)# no ip addressRouter(config-if)# service instance 71 fastethernetRouter(config-if-srv)# encapsulation dot1q 71Router(config-if-srv)# rewrite ingress tag pop 1 symmetricRouter(config-if-srv)# ip verify source vlan dhcp-snoopingRouter(config-if-srv)# bridge-domain 10Related Commands
service instance ethernet
Configures an Ethernet service instance on an interface and enters Ethernet service configuration mode.
local-ip (IPC transport-SCTP local)
To define at least one local IP address that is used to communicate with the local peer, use the local-ip command in IPC transport-SCTP local configuration mode. To remove one or all IP addresses from your configuration, use the no form of this command.
local-ip device-real-ip-address [device-real-ip-address2]
no local-ip device-real-ip-address [device-real-ip-address2]
Syntax Description
Defaults
No IP addresses are defined; thus, peers cannot communicate with the local peer.
Command Modes
IPC transport-SCTP local configuration
Command History
Usage Guidelines
Use the local-ip command to help associate Stream Control Transmission Protocol (SCTP) as the transport protocol between the local and remote peer.
This command is part of a suite of commands used to configure the Stateful Switchover (SSO) protocol. SSO is necessary for IP Security (IPSec) and Internet Key Exchange (IKE) to learn about the redundancy state of the network and to synchronize their internal application state with their redundant peers.
Examples
The following example shows how to enable SSO:
!redundancy inter-devicescheme standby HA-in!!ipc zone defaultassociation 1no shutdownprotocol sctplocal-port 5000local-ip 10.0.0.1remote-port 5000remote-ip 10.0.0.2Related Commands
local-port
To define the local Stream Control Transmission Protocol (SCTP) port that is used to communicate with the redundant peer, use the local-port command in SCTP protocol configuration mode.
local-port local-port-number
Syntax Description
local-port-number
Local port number, which should be the same as the remote port number on the peer router (which is specified via the remote-port command).
Defaults
A local SCTP port is not defined.
Command Modes
SCTP protocol configuration
Command History
Usage Guidelines
The local-port command enters IPC transport-SCTP local configuration mode, which allows you to specify at least one local IP address (via the local-ip command) that is used to communicate with the redundant peer.
Examples
The following example shows how to enable Stateful Switchover (SSO):
!redundancy inter-devicescheme standby HA-in!!ipc zone defaultassociation 1no shutdownprotocol sctplocal-port 5000local-ip 10.0.0.1remote-port 5000remote-ip 10.0.0.2Related Commands
remote-ip (IPC transport-SCTP remote)
To define at least one IP address of the redundant peer that is used to communicate with the local device, use the remote-ip command in IPC transport-SCTP remote configuration mode. To remove one or all IP addresses from your configuration, use the no form of this command.
remote-ip peer-real-ip-address [peer-real-ip-address2]
no remote-ip peer-real-ip-address [peer-real-ip-address2]
Syntax Description
Defaults
No IP addresses are defined.
Command Modes
IPC transport-SCTP remote configuration
Command History
Usage Guidelines
Use the remote-ip command to help associate Stream Control Transmission Protocol (SCTP) as the transport protocol between the local and remote peer.
This command is part of a suite of commands used to configure the Stateful Switch Over (SSO) protocol. SSO is necessary for IP Security (IPSec) and Internet Key Exchange (IKE) to learn about the redundancy state of the network and to synchronize their internal application state with their redundant peers.
Examples
The following example shows how to enable SSO:
redundancy inter-devicescheme standby HA-in!ipc zone defaultassociation 1no shutdownprotocol sctplocal-port 5000local-ip 10.0.0.1remote-port 5000remote-ip 10.0.0.2Related Commands
remote-port
To define the remote Stream Control Transmission Protocol (SCTP) port that is used to communicate with the redundant peer, use the remote-port command in SCTP protocol configuration mode.
remote-port remote-port-number
Syntax Description
remote-port-number
Remote port number, which should be the same as the local port number on the peer router (which is specified via the local-port command).
Defaults
A remote SCTP port is not defined.
Command Modes
SCTP protocol configuration
Command History
Usage Guidelines
The remote-port command enters IPC transport-SCTP remote configuration mode, which allows you to specify at least one remote IP address (via the remote-ip command) that is used to communicate with the redundant peer.
Examples
The following example shows how to enable Stateful Switchover (SSO):
redundancy inter-devicescheme standby HA-in!ipc zone defaultassociation 1no shutdownprotocol sctplocal-port 5000local-ip 10.0.0.1remote-port 5000remote-ip 10.0.0.2Related Commands
show hosts
To display the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses specific to a particular Domain Name System (DNS) view or for all configured DNS views, use the show hosts command in privileged EXEC mode.
show hosts [vrf vrf-name] [view view-name] [all | hostname] [summary]
Syntax Description
Command Modes
Privileged EXEC
Command History
Usage Guidelines
This command displays the default domain name, the style of name lookup service, a list of name server hosts, and the cached list of hostnames and addresses specific to a particular DNS view or for all configured DNS views.
If you specify the show hosts command without any optional keywords or arguments, only the entries in the global hostname cache will be displayed.
If the output from this command extends beyond the bottom of the screen, press the Space bar to continue or press the Q-key to terminate command output.
Examples
The following is sample output from the show hosts command with no parameters specified:
Router# show hostsDefault domain is CISCO.COMName/address lookup uses domain serviceName servers are 192.0.2.220Host Flag Age Type Address(es)EXAMPLE1.CISCO.COM (temp, OK) 1 IP 192.0.2.10EXAMPLE2.CISCO.COM (temp, OK) 8 IP 192.0.2.50EXAMPLE3.CISCO.COM (temp, OK) 8 IP 192.0.2.115EXAMPLE4.CISCO.COM (temp, EX) 8 IP 192.0.2.111EXAMPLE5.CISCO.COM (temp, EX) 0 IP 192.0.2.27EXAMPLE6.CISCO.COM (temp, EX) 24 IP 192.0.2.30The following is sample output from the show hosts command that specifies the VRF vpn101:
Router# show hosts vrf vpn101Default domain is example.comDomain list: example1.com, example2.com, example3.comName/address lookup uses domain serviceName servers are 192.0.2.204, 192.0.2.205, 192.0.2.206Codes: UN - unknown, EX - expired, OK - OK, ?? - revalidatetemp - temporary, perm - permanentNA - Not Applicable None - Not definedHost Port Flags Age Type Address(es)user None (perm, OK) 0 IP 192.0.2.001www.example.com None (perm, OK) 0 IP 192.0.2.111192.0.2.112Table 30 describes the significant fields shown in the display.
Related Commands
show ip aliases
To display the IP addresses mapped to TCP ports (aliases) and Serial Line Internet Protocol (SLIP) addresses, which are treated similar to aliases, use the show ip aliases command in user EXEC or privileged EXEC mode.
show ip aliases
Syntax Description
This command has no arguments or keywords.
Command Modes
User EXEC (>)
Privileged EXEC (#)Command History
Usage Guidelines
To distinguish a SLIP address from a normal alias address, the command output uses the form SLIP TTY1 for the port number, where 1 is the auxiliary port. The display lists the address type, the IP address, and the corresponding port number. The output field descriptions are self-explanatory.
Examples
The following is sample output from the show ip aliases command:
Router# show ip aliasesAddress Type IP Address PortInterface 10.1.1.1 SLIP TTY1Dynamic 198.51.100.1Dynamic 198.51.100.22Dynamic 10.0.0.0Dynamic 10.2.2.2Interface 10.114.11.39 SLIP TTY1Interface 172.31.232.182 SLIP TTY1Interface 192.0.2.11 SLIP TTY1Dynamic 209.165.200.225Interface 209.165.200.225Related Commands
show ip interface
To display the usability status of interfaces configured for IP, use the show ip interface command in privileged EXEC mode.
show ip interface [type number] [brief]
Syntax Description
type
(Optional) Interface type.
number
(Optional) Interface number.
brief
(Optional) Displays a summary of the usability status information for each interface.
Command Default
The full usability status is displayed for all interfaces configured for IP.
Command Modes
Privileged EXEC (#)
Command History
Usage Guidelines
The Cisco IOS software automatically enters a directly-connected route in the routing table if the interface is usable (which means that it can send and receive packets). If an interface is not usable, the directly-connected routing entry is removed from the routing table. Removing the entry lets the software use dynamic routing protocols to determine backup routes to the network, if any.
If the interface can provide two-way communication, the line protocol is marked "up." If the interface hardware is usable, the interface is marked "up."
If you specify an optional interface type, you see information for that specific interface. If you specify no optional arguments, you see information on all the interfaces.
When an asynchronous interface is encapsulated with PPP or Serial Line Internet Protocol (SLIP), IP fast switching is enabled. A show ip interface command on an asynchronous interface encapsulated with PPP or SLIP displays a message indicating that IP fast switching is enabled.
You can use the show ip interface brief command to view a summary of the router interfaces. This command displays the IP address, the interface status, and other information.
The show ip interface brief command does not display any information related to Unicast RPF.
Examples
The following example shows configuration information on interface Gigabit Ethernet 0/3. In this example, the IP flow egress feature is configured on the output side (where packets go out of the interface), and the policy route-map named PBR_NAME is configured on the input side (where packets come into the interface).
Router# show running-config interface gigabitethernet 0/3interface GigabitEthernet0/3ip address 10.1.1.1 255.255.0.0ip flow egressip policy route-map PBR_NAMEduplex autospeed automedia-type gbicnegotiation autoendThe following example shows interface information on Gigabit Ethernet interface 0/3. In this example, MPF is enabled, and both features are not supported by MPF and are ignored.
Router# show ip interface gigabitethernet 0/3GigabitEthernet0/3 is up, line protocol is upInternet address is 10.1.1.1/16Broadcast address is 255.255.255.255Address determined by setup commandMTU is 1500 bytesHelper address is not setDirected broadcast forwarding is disabledOutgoing access list is not setInbound access list is not setProxy ARP is enabledLocal Proxy ARP is disabledSecurity level is defaultSplit horizon is enabledICMP redirects are always sentICMP unreachables are always sentICMP mask replies are never sentIP fast switching is enabledIP fast switching on the same interface is disabledIP Flow switching is disabledIP CEF switching is enabledIP Feature Fast switching turbo vectorIP VPN Flow CEF switching turbo vectorIP multicast fast switching is enabledIP multicast distributed fast switching is disabledIP route-cache flags are Fast, CEFRouter Discovery is disabledIP output packet accounting is disabledIP access violation accounting is disabledTCP/IP header compression is disabledRTP/IP header compression is disabledPolicy routing is enabled, using route map PBRNetwork address translation is disabledBGP Policy Mapping is disabledIP Multi-Processor Forwarding is enabledIP Input features, "PBR",are not supported by MPF and are IGNOREDIP Output features, "NetFlow",are not supported by MPF and are IGNOREDThe following example identifies a downstream VRF instance. In the example, "Downstream VPN Routing/Forwarding "D"" identifies the downstream VRF instance.
Router# show ip interface virtual-access 3Virtual-Access3 is up, line protocol is upInterface is unnumbered. Using address of Loopback2 (10.0.0.8)Broadcast address is 255.255.255.255Peer address is 10.8.1.1MTU is 1492 bytesHelper address is not setDirected broadcast forwarding is disabledOutgoing access list is not setInbound access list is not setProxy ARP is enabledLocal Proxy ARP is disabledSecurity level is defaultSplit horizon is enabledICMP redirects are always sentICMP unreachables are always sentICMP mask replies are never sentIP fast switching is enabledIP fast switching on the same interface is enabledIP Flow switching is disabledIP CEF switching is enabledIP Feature Fast switching turbo vectorIP VPN CEF switching turbo vectorVPN Routing/Forwarding "U"Downstream VPN Routing/Forwarding "D"IP multicast fast switching is disabledIP multicast distributed fast switching is disabledIP route-cache flags are Fast, CEFRouter Discovery is disabledIP output packet accounting is disabledIP access violation accounting is disabledTCP/IP header compression is disabledRTP/IP header compression is disabledPolicy routing is disabledNetwork address translation is disabledWCCP Redirect outbound is disabledWCCP Redirect inbound is disabledWCCP Redirect exclude is disabledBGP Policy Mapping is disabledThe following example shows the information displayed when Unicast RPF drop-rate notification is configured:
Router# show ip interface ethernet 2/3Ethernet2/3 is up, line protocol is upInternet address is 10.0.0.4/16Broadcast address is 255.255.255.255Address determined by non-volatile memoryMTU is 1500 bytesHelper address is not setDirected broadcast forwarding is disabledOutgoing access list is not setInbound access list is not setProxy ARP is enabledLocal Proxy ARP is disabledSecurity level is defaultSplit horizon is enabledICMP redirects are always sentICMP unreachables are always sentICMP mask replies are never sentIP fast switching is disabledIP Flow switching is disabledIP CEF switching is disabledIP Null turbo vectorIP Null turbo vectorIP multicast fast switching is disabledIP multicast distributed fast switching is disabledIP route-cache flags are No CEFRouter Discovery is disabledIP output packet accounting is disabledIP access violation accounting is disabledTCP/IP header compression is disabledRTP/IP header compression is disabledProbe proxy name replies are disabledPolicy routing is disabledNetwork address translation is disabledWCCP Redirect outbound is disabledWCCP Redirect inbound is disabledWCCP Redirect exclude is disabledBGP Policy Mapping is disabledUnicast RPF Information
Input features: uRPFIP verify source reachable-via RX, allow default0 verification drops0 suppressed verification drops0 verification drop-rateRouter#The following example shows how to display the usability status for a specific VLAN:
Router# show ip interface vlan 1Vlan1 is up, line protocol is upInternet address is 10.0.0.4/24Broadcast address is 255.255.255.255Address determined by non-volatile memoryMTU is 1500 bytesHelper address is not setDirected broadcast forwarding is disabledOutgoing access list is not setInbound access list is not setProxy ARP is enabledLocal Proxy ARP is disabledSecurity level is defaultSplit horizon is enabledICMP redirects are always sentICMP unreachables are always sentICMP mask replies are never sentIP fast switching is enabledIP fast switching on the same interface is disabledIP Flow switching is disabledIP CEF switching is enabledIP Fast switching turbo vectorIP Normal CEF switching turbo vectorIP multicast fast switching is enabledIP multicast distributed fast switching is disabledIP route-cache flags are Fast, CEFRouter Discovery is disabledIP output packet accounting is disabledIP access violation accounting is disabledTCP/IP header compression is disabledRTP/IP header compression is disabledProbe proxy name replies are disabledPolicy routing is disabledNetwork address translation is disabledWCCP Redirect outbound is disabledWCCP Redirect inbound is disabledWCCP Redirect exclude is disabledBGP Policy Mapping is disabledSampled Netflow is disabledIP multicast multilayer switching is disabledNetflow Data Export (hardware) is enabledTable 31 describes the significant fields shown in the display.
The following example shows how to display a summary of the usability status information for each interface:
Router# show ip interface briefInterface IP-Address OK? Method Status ProtocolEthernet0 10.108.00.5 YES NVRAM up upEthernet1 unassigned YES unset administratively down downLoopback0 10.108.200.5 YES NVRAM up upSerial0 10.108.100.5 YES NVRAM up upSerial1 10.108.40.5 YES NVRAM up upSerial2 10.108.100.5 YES manual up upSerial3 unassigned YES unset administratively down downTable 32 describes the significant fields shown in the display.
Related Commands
show ip irdp
To display ICMP Router Discovery Protocol (HRDP) values, use the show ip irdp command in EXEC mode.
show ip irdp
Syntax Description
This command has no arguments or keywords.
Command Modes
EXEC
Command History
Examples
The following is sample output from the show ip irdp command:
Router# show ip irdpEthernet 0 has router discovery enabledAdvertisements will occur between every 450 and 600 seconds.Advertisements are valid for 1800 seconds.Default preference will be 100.--More--Serial 0 has router discovery disabled--More--Ethernet 1 has router discovery disabledAs the display shows, show ip irdp output indicates whether router discovery has been configured for each router interface, and it lists the values of router discovery configurables for those interfaces on which router discovery has been enabled. Explanations for the less obvious lines of output in the display are as follows:
Advertisements will occur between every 450 and 600 seconds.This indicates the configured minimum and maximum advertising interval for the interface.
Advertisements are valid for 1800 seconds.This indicates the configured holdtime values for the interface.
Default preference will be 100.This indicates the configured (or in this case default) preference value for the interface.
Related Commands
show ip masks
To display the masks used for network addresses and the number of subnets using each mask, use the show ip masks command in EXEC mode.
show ip masks address
Syntax Description
Command Modes
EXEC
Command History
Usage Guidelines
The show ip masks command is useful for debugging when a variable-length subnet mask (VLSM) is used. It shows the number of masks associated with the network and the number of routes for each mask.
Examples
The following is sample output from the show ip masks command:
Router# show ip masks 172.16.0.0Mask Reference count255.255.255.255 2255.255.255.0 3255.255.0.0 1show ip route
To display the current state of the routing table, use the show ip route command in user EXEC or privileged EXEC mode.
show ip route [ip-address [repair-paths | next-hop-override [dhcp] | mask [longer-prefixes]] | protocol [process-id] | list [access-list-number | access-list-name] | static download | update-queue]
Syntax Description
Command Modes
User EXEC (>)
Privileged EXEC (#)Command History
Usage Guidelines
The show ip route static download command provides a way to display all dynamic static routes with name and distance information, including active and inactive ones. You can display all active dynamic static routes with both the show ip route and show ip route static commands after these active routes are added in the main routing table.
Examples
Routing Table Examples
The following examples show the standard routing tables displayed by the show ip route command. Use the codes displayed at the beginning of each report and the information in Table 35 to understand the type of route.
The following is sample output from the show ip route command when entered without an address:
Router# show ip routeCodes: R - RIP derived, O - OSPF derived,C - connected, S - static, B - BGP derived,* - candidate default route, IA - OSPF inter area route,i - IS-IS derived, ia - IS-IS, U - per-user static route,o - on-demand routing, M - mobile, P - periodic downloaded static route,D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route,E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route,N2 - OSPF NSSA external type 2 routeGateway of last resort is 10.119.254.240 to network 10.140.0.0O E2 10.110.0.0 [160/5] via 10.119.254.6, 0:01:00, Ethernet2E 10.67.10.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2O E2 10.68.132.0 [160/5] via 10.119.254.6, 0:00:59, Ethernet2O E2 10.130.0.0 [160/5] via 10.119.254.6, 0:00:59, Ethernet2E 10.128.0.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2E 10.129.0.0 [200/129] via 10.119.254.240, 0:02:22, Ethernet2E 10.65.129.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2E 10.10.0.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2E 10.75.139.0 [200/129] via 10.119.254.240, 0:02:23, Ethernet2E 10.16.208.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2E 10.84.148.0 [200/129] via 10.119.254.240, 0:02:23, Ethernet2E 10.31.223.0 [200/128] via 10.119.254.244, 0:02:22, Ethernet2E 10.44.236.0 [200/129] via 10.119.254.240, 0:02:23, Ethernet2E 10.141.0.0 [200/129] via 10.119.254.240, 0:02:22, Ethernet2E 10.140.0.0 [200/129] via 10.119.254.240, 0:02:23, Ethernet2The following is sample output that includes IS-IS Level 2 routes learned:
Router# show ip routeCodes: L- Local R - RIP derived, O - OSPF derived,C - connected, S - static, B - BGP derived,* - candidate default route, IA - OSPF inter area route,i - IS-IS derived, ia - IS-IS, U - per-user static route,o - on-demand routing, M - mobile, P - periodic downloaded static route,D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route,E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route,N2 - OSPF NSSA external type 2 routeGateway of last resort is 192.168.1.2 to network 0.0.0.0S* 0.0.0.0/0 [1/0] via 192.168.1.210.0.0.0/8 is variably subnetted, 2 subnets, 2 masksC 10.10.10.0/24 is directly connected, Vlan1L 10.10.10.1/32 is directly connected, Vlan1192.168.1.0/24 is variably subnetted, 2 subnets, 2 masksC 192.168.1.0/30 is directly connected, GigabitEthernet0L 192.168.1.1/32 is directly connected, GigabitEthernet0The following is sample output using the longer-prefixes keyword. When the longer-prefixes keyword is included, the address and mask pair becomes the prefix, and any address that matches that prefix is displayed. Therefore, multiple addresses are displayed.
In the following example, the logical AND operation is performed on the source address 10.0.0.0 and the mask 10.0.0.0, resulting in 10.0.0.0. Each destination in the routing table is also logically ANDed with the mask and compared to that result of 10.0.0.0. Any destinations that fall into that range are displayed in the output.
Router# show ip route 10.0.0.0 10.0.0.0 longer-prefixesCodes: L - Local R - RIP derived, O - OSPF derived,C - connected, S - static, B - BGP derived,* - candidate default route, IA - OSPF inter area route,i - IS-IS derived, ia - IS-IS, U - per-user static route,o - on-demand routing, M - mobile, P - periodic downloaded static route,D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route,E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route,N2 - OSPF NSSA external type 2 routeGateway of last resort is not set10.0.0.0/8 is variably subnetted, 2 subnets, 2 masksC 10.4.9.0/24 is directly connected, GigabitEthernet0/1L 10.4.9.134/32 is directly connected, GigabitEthernet0/1171.69.0.0/16 is variably subnetted, 2 subnets, 2 masksS 171.69.0.0/16 [1/0] via 10.4.9.1S 171.69.1.129/32 [1/0] via 10.4.9.1The following examples display all downloaded static routes. A P designates which route was installed using AAA route download.
Router# show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, * - candidate defaultU - per-user static route, o - ODR, P - periodic downloaded static routeT - traffic engineered routeGateway of last resort is 172.21.17.1 to network 0.0.0.0172.31.0.0/32 is subnetted, 1 subnetsP 172.31.229.41 is directly connected, Dialer1 20.0.0.0/24 is subnetted, 3 subnetsP 10.1.1.0 [200/0] via 172.31.229.41, Dialer1P 10.1.3.0 [200/0] via 172.31.229.41, Dialer1P 10.1.2.0 [200/0] via 172.31.229.41, Dialer1Router# show ip route static172.27.4.0/8 is variably subnetted, 2 subnets, 2 masksP 172.16.1.1/32 is directly connected, BRI0P 172.27.4.0/8 [1/0] via 10.1.1.1, BRI0S 172.31.0.0/16 [1/0] via 172.21.114.65, Ethernet0S 10.0.0.0/8 is directly connected, BRI0P 10.0.0.0/8 is directly connected, BRI0172.21.0.0/16 is variably subnetted, 5 subnets, 2 masksS 172.21.114.201/32 is directly connected, BRI0S 172.21.114.205/32 is directly connected, BRI0S 172.21.114.174/32 is directly connected, BRI0S 172.21.114.12/32 is directly connected, BRI0P 10.0.0.0/8 is directly connected, BRI0P 10.1.0.0/16 is directly connected, BRI0P 10.2.2.0/24 is directly connected, BRI0S* 0.0.0.0/0 [1/0] via 172.21.114.65, Ethernet0S 172.29.0.0/16 [1/0] via 172.21.114.65, Ethernet0The following example shows how to use the show ip route static download command to display all active and inactive routes installed using AAA route download:
Router# show ip route static downloadConnectivity: A - Active, I - InactiveA 10.10.0.0 255.0.0.0 BRI0A 10.11.0.0 255.0.0.0 BRI0A 10.12.0.0 255.0.0.0 BRI0A 10.13.0.0 255.0.0.0 BRI0I 10.20.0.0 255.0.0.0 172.21.1.1I 10.22.0.0 255.0.0.0 Serial0I 10.30.0.0 255.0.0.0 Serial0I 10.31.0.0 255.0.0.0 Serial1I 10.32.0.0 255.0.0.0 Serial1A 10.34.0.0 255.0.0.0 192.168.1.1A 10.36.1.1 255.255.255.255 BRI0 200 name remote1I 10.38.1.9 255.255.255.0 192.168.69.1The following example shows how to use the show ip route nhrp command to enable shortcut switching on the tunnel interface:
Router# show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRPGateway of last resort is not set10.0.0.0/16 is variably subnetted, 3 subnets, 2 masksC 10.1.1.0/24 is directly connected, Tunnel0C 172.16.22.0 is directly connected, Ethernet1/0H 172.16.99.0 [250/1] via 10.1.1.99, 00:11:43, Tunnel010.11.0.0/24 is subnetted, 1 subnetsC 10.11.11.0 is directly connected, Ethernet0/0Router# show ip route nhrpH 172.16.99.0 [250/1] via 10.1.1.99, 00:11:43, Tunnel0The following is sample output using the next-hop-override keyword. When the next-hop-override keyword is included, the NHRP Nexthop-overrides associated with a particular route, along with the corresponding default next hops, are displayed.
===============================================================1) Initial configuration===============================================================Router# show ip routeCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated routeGateway of last resort is not set10.2.0.0/16 is variably subnetted, 2 subnets, 2 masksC 10.2.1.0/24 is directly connected, Loopback1L 10.2.1.1/32 is directly connected, Loopback110.0.0.0/24 is subnetted, 1 subnetsS 10.10.10.0 is directly connected, Tunnel010.11.0.0/24 is subnetted, 1 subnetsS 10.11.11.0 is directly connected, Ethernet0/0Router# show ip route next-hop-overrideCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated routeGateway of last resort is not set10.2.0.0/16 is variably subnetted, 2 subnets, 2 masksC 10.2.1.0/24 is directly connected, Loopback1L 10.2.1.1/32 is directly connected, Loopback110.0.0.0/24 is subnetted, 1 subnetsS 10.10.10.0 is directly connected, Tunnel010.11.0.0/24 is subnetted, 1 subnetsS 10.11.11.0 is directly connected, Ethernet0/0Router# show ip cefPrefix Next Hop Interface...10.2.1.255/32 receive Loopback110.10.10.0/24 attached Tunnel0 <<<<<<<<10.11.11.0/24 attached Ethernet0/0127.0.0.0/8 drop...===============================================================2) Add a Nexthop-overrideaddress = 10.10.10.0mask = 255.255.255.0gateway = 10.1.1.1interface = Tunnel0===============================================================Router# show ip routeCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated routeGateway of last resort is not set10.2.0.0/16 is variably subnetted, 2 subnets, 2 masksC 10.2.1.0/24 is directly connected, Loopback1L 10.2.1.1/32 is directly connected, Loopback110.0.0.0/24 is subnetted, 1 subnets% S 10.10.10.0 is directly connected, Tunnel010.11.0.0/24 is subnetted, 1 subnetsS 10.11.11.0 is directly connected, Ethernet0/0Router# show ip route next-hop-overrideCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated routeGateway of last resort is not set10.2.0.0/16 is variably subnetted, 2 subnets, 2 masksC 10.2.1.0/24 is directly connected, Loopback1L 10.2.1.1/32 is directly connected, Loopback110.0.0.0/24 is subnetted, 1 subnets% S 10.10.10.0 is directly connected, Tunnel0[NHO][1/0] via 10.1.1.1, Tunnel010.11.0.0/24 is subnetted, 1 subnetsS 10.11.11.0 is directly connected, Ethernet0/0Router# show ip cefPrefix Next Hop Interface...10.2.1.255/32 receive Loopback110.10.10.0/2410.10.10.0/24 10.1.1.1 Tunnel010.11.11.0/24 attached Ethernet0/010.12.0.0/16 drop...===============================================================3) Delete a Nexthop-overrideaddress = 10.10.10.0mask = 255.255.255.0gateway = 10.11.1.1interface = Tunnel0===============================================================Router# show ip routeCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated routeGateway of last resort is not set10.2.0.0/16 is variably subnetted, 2 subnets, 2 masksC 10.2.1.0/24 is directly connected, Loopback1L 10.2.1.1/32 is directly connected, Loopback110.0.0.0/24 is subnetted, 1 subnetsS 10.10.10.0 is directly connected, Tunnel010.11.0.0/24 is subnetted, 1 subnetsS 10.11.11.0 is directly connected, Ethernet0/0Router# show ip route next-hop-overrideCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated routeGateway of last resort is not set10.2.0.0/16 is variably subnetted, 2 subnets, 2 masksC 10.2.1.0/24 is directly connected, Loopback1L 10.2.1.1/32 is directly connected, Loopback110.0.0.0/24 is subnetted, 1 subnetsS 10.10.10.0 is directly connected, Tunnel010.11.0.0/24 is subnetted, 1 subnetsS 10.11.11.0 is directly connected, Ethernet0/0Router# show ip cefPrefix Next Hop Interface...10.2.1.255/32 receive Loopback110.10.10.0/2410.10.10.0/24 attached Tunnel010.11.11.0/24 attached Ethernet0/010.120.0.0/16 drop...
Specific Route Information
When you specify that you want information about a specific network displayed, more detailed statistics are shown. The following is sample output from the show ip route command when entered with the IP address 10.0.0.1:
Router# show ip route 10.0.0.1Routing entry for 10.0.0.1/32Known via "isis", distance 115, metric 20, type level-1Redistributing via isisLast update from 10.191.255.251 on Fddi1/0, 00:00:13 agoRouting Descriptor Blocks:* 10.22.22.2, from 10.191.255.247, via Serial2/3Route metric is 20, traffic share count is 110.191.255.251, from 10.191.255.247, via Fddi1/0Route metric is 20, traffic share count is 1When an IS-IS router advertises its link-state information, it includes one of its own IP addresses to be used as the originator IP address. When other routers calculate IP routes, they can store the originator IP address with each route in the routing table.
The preceding example shows the output from the show ip route command for an IP route generated by IS-IS. Each path that is shown under the Routing Descriptor Blocks report displays two IP addresses. The first address (10.22.22.2) is the next hop address. The second is the originator IP address from the advertising IS-IS router. This address helps you determine where a particular IP route has originated in your network. In the example the route to 10.0.0.1/32 was originated by a router with IP address 10.191.255.247.
Table 36 describes the significant fields shown when using the show ip route command with an IP address.
The following is sample output using the longer-prefixes keyword. When the longer-prefixes keyword is included, the address and mask pair becomes the prefix, and any address that matches that prefix is displayed. Therefore, multiple addresses are displayed.
In the following example, the logical AND operation is performed on the source address 10.0.0.0 and the mask 10.0.0.0, resulting in 10.0.0.0. Each destination in the routing table is also logically ANDed with the mask and compared to that result of 10.0.0.0. Any destinations that fall into that range are displayed in the output.
Router# show ip route 10.0.0.0 10.0.0.0 longer-prefixesCodes: R - RIP derived, O - OSPF derived,C - connected, S - static, B - BGP derived,* - candidate default route, IA - OSPF inter area route,i - IS-IS derived, ia - IS-IS, U - per-user static route,o - on-demand routing, M - mobile, P - periodic downloaded static route,D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route,E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route,N2 - OSPF NSSA external type 2 routeGateway of last resort is not setS 10.134.0.0 is directly connected, Ethernet0S 10.10.0.0 is directly connected, Ethernet0S 10.129.0.0 is directly connected, Ethernet0S 10.128.0.0 is directly connected, Ethernet0S 10.49.246.0 is directly connected, Ethernet0S 10.160.97.0 is directly connected, Ethernet0S 10.153.88.0 is directly connected, Ethernet0S 10.76.141.0 is directly connected, Ethernet0S 10.75.138.0 is directly connected, Ethernet0S 10.44.237.0 is directly connected, Ethernet0S 10.31.222.0 is directly connected, Ethernet0S 10.16.209.0 is directly connected, Ethernet0S 10.145.0.0 is directly connected, Ethernet0S 10.141.0.0 is directly connected, Ethernet0S 10.138.0.0 is directly connected, Ethernet0S 10.128.0.0 is directly connected, Ethernet010.19.0.0 255.255.255.0 is subnetted, 1 subnetsC 10.19.64.0 is directly connected, Ethernet010.69.0.0 is variably subnetted, 2 subnets, 2 masksC 10.69.232.32 255.255.255.240 is directly connected, Ethernet0S 10.69.0.0 255.255.0.0 is directly connected, Ethernet0The following output includes the tag 120 applied to the route 10.22.0.0/16. You must specify an IP prefix in order to see the tag value.
Router# show ip route 10.22.0.0Routing entry for 10.22.0.0/16Known via "isis", distance 115, metric 12Tag 120, type level-1Redistributing via isisLast update from 172.19.170.12 on Ethernet2, 01:29:13 agoRouting Descriptor Blocks:* 172.19.170.12, from 10.3.3.3, via Ethernet2Route metric is 12, traffic share count is 1Route tag 120Static Routes Using a DHCP Gateway Examples
The following example shows that IP route 10.8.8.0 is directly connected to the Internet and is the next-hop (option 3) default gateway. Routes 10.1.1.1 [1/0], 10.3.2.1 [24/0], and 172.2.2.2 [1/0] are static, and route 10.0.0.0/0 is a default route candidate.
Router# show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static routeGateway of last resort is 10.0.19.14 to network 0.0.0.010.0.0.0/24 is subnetted, 1 subnetsC 10.8.8.0 is directly connected, Ethernet110.0.0.0/32 is subnetted, 1 subnetsS 10.1.1.1 [1/0] via 10.8.8.110.0.0.0/32 is subnetted, 1 subnetsS 10.3.2.1 [24/0] via 10.8.8.1172.16.0.0/32 is subnetted, 1 subnetsS 172.2.2.2 [1/0] via 10.8.8.110.0.0.0/28 is subnetted, 1 subnetsC 10.0.19.0 is directly connected, Ethernet010.0.0.0/24 is subnetted, 1 subnetsC 10.15.15.0 is directly connected, Loopback0S* 10.0.0.0/0 [1/0] via 10.0.19.14The following sample output from the show ip route repair-paths command shows the repair paths marked with the tag [RPR]:
Router# show ip route repair-pathsCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated route, % - next hop overrideGateway of last resort is not set10.0.0.0/32 is subnetted, 3 subnetsC 10.1.1.1 is directly connected, Loopback0B 10.2.2.2 [200/0] via 172.16.1.2, 00:31:07[RPR][200/0] via 192.168.1.2, 00:31:07B 10.9.9.9 [20/0] via 192.168.1.2, 00:29:45[RPR][20/0] via 192.168.3.2, 00:29:45172.16.0.0/16 is variably subnetted, 2 subnets, 2 masksC 172.16.1.0/24 is directly connected, Ethernet0/0L 172.16.1.1/32 is directly connected, Ethernet0/0192.168.1.0/24 is variably subnetted, 2 subnets, 2 masksC 192.168.1.0/24 is directly connected, Serial2/0L 192.168.1.1/32 is directly connected, Serial2/0B 192.168.3.0/24 [200/0] via 172.16.1.2, 00:31:07[RPR][200/0] via 192.168.1.2, 00:31:07B 192.168.9.0/24 [20/0] via 192.168.1.2, 00:29:45[RPR][20/0] via 192.168.3.2, 00:29:45B 192.168.13.0/24 [20/0] via 192.168.1.2, 00:29:45[RPR][20/0] via 192.168.3.2, 00:29:45Router# show ip route repair-paths 10.9.9.9>Routing entry for 10.9.9.9/32> Known via "bgp 100", distance 20, metric 0> Tag 10, type external> Last update from 192.168.1.2 00:44:52 ago> Routing Descriptor Blocks:> * 192.168.1.2, from 192.168.1.2, 00:44:52 ago, recursive-via-conn> Route metric is 0, traffic share count is 1> AS Hops 2> Route tag 10> MPLS label: none> [RPR]192.168.3.2, from 172.16.1.2, 00:44:52 ago> Route metric is 0, traffic share count is 1> AS Hops 2> Route tag 10> MPLS label: none
Specific Route Information
When you specify that you want information about a specific network displayed, more detailed statistics are shown. The following is sample output from the show ip route command when entered with the IP address 10.0.0.1:
Router# show ip route 10.0.0.1Routing entry for 10.0.0.1/32Known via "isis", distance 115, metric 20, type level-1Redistributing via isisLast update from 10.191.255.251 on Fddi1/0, 00:00:13 agoRouting Descriptor Blocks:* 10.22.22.2, from 10.191.255.247, via Serial2/3Route metric is 20, traffic share count is 110.191.255.251, from 10.191.255.247, via Fddi1/0Route metric is 20, traffic share count is 1When an IS-IS router advertises its link-state information, it includes one of its own IP addresses to be used as the originator IP address. When other routers calculate IP routes, they can store the originator IP address with each route in the routing table.
The example above shows the output from the show ip route command when looking at an IP route generated by IS-IS. Each path that is shown under the Routing Descriptor Blocks report displays two IP addresses. The first address (10.22.22.2) is the next hop address. The second is the originator IP address from the advertising IS-IS router. This address helps you determine where a particular IP route has originated in your network. In the example the route to 10.0.0.1/32 was originated by a router with IP address 10.191.255.247.
Table 36 describes the significant fields shown when using the show ip route command with an IP address.
The following is sample output using the longer-prefixes keyword. When the longer-prefixes keyword is included, the address and mask pair becomes the prefix, and any address that matches that prefix is displayed. Therefore, multiple addresses are displayed.
In the following example, the logical AND operation is performed on the source address 10.0.0.0 and the mask 10.0.0.0, resulting in 10.0.0.0. Each destination in the routing table is also logically ANDed with the mask and compared to that result of 10.0.0.0. Any destinations that fall into that range are displayed in the output.
Router# show ip route 10.0.0.0 10.0.0.0 longer-prefixesCodes: R - RIP derived, O - OSPF derived,C - connected, S - static, B - BGP derived,* - candidate default route, IA - OSPF inter area route,i - IS-IS derived, ia - IS-IS, U - per-user static route,o - on-demand routing, M - mobile, P - periodic downloaded static route,D - EIGRP, EX - EIGRP external, E1 - OSPF external type 1 route,E2 - OSPF external type 2 route, N1 - OSPF NSSA external type 1 route,N2 - OSPF NSSA external type 2 routeGateway of last resort is not setS 10.134.0.0 is directly connected, Ethernet0S 10.10.0.0 is directly connected, Ethernet0S 10.129.0.0 is directly connected, Ethernet0S 10.128.0.0 is directly connected, Ethernet0S 10.49.246.0 is directly connected, Ethernet0S 10.160.97.0 is directly connected, Ethernet0S 10.153.88.0 is directly connected, Ethernet0S 10.76.141.0 is directly connected, Ethernet0S 10.75.138.0 is directly connected, Ethernet0S 10.44.237.0 is directly connected, Ethernet0S 10.31.222.0 is directly connected, Ethernet0S 10.16.209.0 is directly connected, Ethernet0S 10.145.0.0 is directly connected, Ethernet0S 10.141.0.0 is directly connected, Ethernet0S 10.138.0.0 is directly connected, Ethernet0S 10.128.0.0 is directly connected, Ethernet010.19.0.0 255.255.255.0 is subnetted, 1 subnetsC 10.19.64.0 is directly connected, Ethernet010.69.0.0 is variably subnetted, 2 subnets, 2 masksC 10.69.232.32 255.255.255.240 is directly connected, Ethernet0S 10.69.0.0 255.255.0.0 is directly connected, Ethernet0The following output includes the tag 120 applied to the route 10.22.0.0/16. You must specify an IP prefix in order to see the tag value.
Router# show ip route 10.22.0.0Routing entry for 10.22.0.0/16Known via "isis", distance 115, metric 12Tag 120, type level-1Redistributing via isisLast update from 172.19.170.12 on Ethernet2, 01:29:13 agoRouting Descriptor Blocks:* 172.19.170.12, from 10.3.3.3, via Ethernet2Route metric is 12, traffic share count is 1Route tag 120Static Routes Using a DHCP Gateway Examples
The following example shows that IP route 10.8.8.0 is directly connected to the Internet and is the next-hop (option 3) default gateway. Routes 10.1.1.1 [1/0], 10.3.2.1 [24/0], and 172.2.2.2 [1/0] are static, and route 10.0.0.0/0 is a default route candidate.
Router# show ip routeCodes: C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static routeGateway of last resort is 10.0.19.14 to network 0.0.0.010.0.0.0/24 is subnetted, 1 subnetsC 10.8.8.0 is directly connected, Ethernet110.0.0.0/32 is subnetted, 1 subnetsS 10.1.1.1 [1/0] via 10.8.8.110.0.0.0/32 is subnetted, 1 subnetsS 10.3.2.1 [24/0] via 10.8.8.1172.16.0.0/32 is subnetted, 1 subnetsS 172.2.2.2 [1/0] via 10.8.8.110.0.0.0/28 is subnetted, 1 subnetsC 10.0.19.0 is directly connected, Ethernet010.0.0.0/24 is subnetted, 1 subnetsC 10.15.15.0 is directly connected, Loopback0S* 10.0.0.0/0 [1/0] via 10.0.19.14The following sample output from the show ip route repair-paths command shows the repair paths marked with the tag [RPR]:
Router# show ip route repair-pathsCodes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter areaN1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2E1 - OSPF external type 1, E2 - OSPF external type 2i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2ia - IS-IS inter area, * - candidate default, U - per-user static routeo - ODR, P - periodic downloaded static route, H - NHRP+ - replicated route, % - next hop overrideGateway of last resort is not set10.0.0.0/32 is subnetted, 3 subnetsC 10.1.1.1 is directly connected, Loopback0B 10.2.2.2 [200/0] via 172.16.1.2, 00:31:07[RPR][200/0] via 192.168.1.2, 00:31:07B 10.9.9.9 [20/0] via 192.168.1.2, 00:29:45[RPR][20/0] via 192.168.3.2, 00:29:45172.16.0.0/16 is variably subnetted, 2 subnets, 2 masksC 172.16.1.0/24 is directly connected, Ethernet0/0L 172.16.1.1/32 is directly connected, Ethernet0/0192.168.1.0/24 is variably subnetted, 2 subnets, 2 masksC 192.168.1.0/24 is directly connected, Serial2/0L 192.168.1.1/32 is directly connected, Serial2/0B 192.168.3.0/24 [200/0] via 172.16.1.2, 00:31:07[RPR][200/0] via 192.168.1.2, 00:31:07B 192.168.9.0/24 [20/0] via 192.168.1.2, 00:29:45[RPR][20/0] via 192.168.3.2, 00:29:45B 192.168.13.0/24 [20/0] via 192.168.1.2, 00:29:45[RPR][20/0] via 192.168.3.2, 00:29:45Router# show ip route repair-paths 10.9.9.9>Routing entry for 10.9.9.9/32> Known via "bgp 100", distance 20, metric 0> Tag 10, type external> Last update from 192.168.1.2 00:44:52 ago> Routing Descriptor Blocks:> * 192.168.1.2, from 192.168.1.2, 00:44:52 ago, recursive-via-conn> Route metric is 0, traffic share count is 1> AS Hops 2> Route tag 10> MPLS label: none> [RPR]192.168.3.2, from 172.16.1.2, 00:44:52 ago> Route metric is 0, traffic share count is 1> AS Hops 2> Route tag 10> MPLS label: noneRelated Commands
show ip source binding
To display IP-source bindings configured on the system, use the show ip source command command in privileged EXEC mode.
show ip source binding [ip-address] [mac-address] [dhcp-snooping | static] [vlan vlan-id] [interface type mod/port]
Syntax Description
Command Default
Both static and DHCP-snooping bindings are displayed.
Command Modes
Privileged EXEC
Command History
Usage Guidelines
Each optional parameter is used to filter the display output.
Examples
This example shows the output without entering any keywords:
Router# show ip source binding
MacAddress IpAddress Lease(sec) Type VLAN Interface------------------ --------------- ---------- ------------- ---- --------------------00:00:00:0A:00:0B 17.16.0.1 infinite static 10 FastEthernet6/1000:00:00:0A:00:0A 17.16.0.2 10000 dhcp-snooping 10 FastEthernet6/11This example shows how to display the static IP binding entry for a specific IP address:
Router# show ip source binding 17.16.0.1 0000.000A.000B static vlan 10 interface gigabitethernet6/10MacAddress IpAddress Lease(sec) Type VLAN Interface------------------ --------------- ---------- ------------- ---- --------------------00:00:00:0A:00:0B 17.16.0.1 infinite static 10 FastEthernet6/10Table 37 describes the significant fields in the display.
Related Commands
show ip verify source
To display the IP source guard configuration and filters on a particular interface, use the show ip verify source command in EXEC mode.
show ip verify source [interface type mod/port] [efp_id efp_id ]
Syntax Description
Defaults
This command has no default settings.
Command Modes
EXEC (#)
Command History
12.2(33)SXH
This command was introduced.
12.2(33)SRD
The efp_id efp_id keyword and argument were added.
Usage Guidelines
Enable port security first because the DHCP security MAC filter cannot apply to the port or VLAN.
Examples
This example shows the display when DHCP snooping is enabled on VLANs 10 to 20, the interface has IP source filter mode that is configured as IP, and there is an existing IP address binding 10.0.0.1 on VLAN 10:
Router# show ip verify source interface gigabitethernet6/1Interface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- -------------- ---------gi6/1 ip active 10.0.0.1 10gi6/1 ip active deny-all 11-20This example shows how to display the IP source guard configuration and filters on a specific interface:
Router# show ip verify source interface gigabitethernet6/1Interface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- -------------- ---------gi6/1 ip inactive-trust-portThis example shows the display when the interface does not have a VLAN enabled for DHCP snooping:
Router# show ip verify source interface gigabitethernet6/3Interface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- -------------- ---------gi6/3 ip inactive-no-snooping-vlanThis example shows the display when the interface has an IP source filter mode that is configured as IP MAC and an existing IP MAC binds 10.0.0.2/aaaa.bbbb.cccc on VLAN 10 and 10.0.0.1/aaaa.bbbb.cccd on VLAN 11:
Router# show ip verify source interface gigabitethernet6/4Interface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- -------------- ---------gi6/4 ip-mac active 10.0.0.2 aaaa.bbbb.cccc 10gi6/4 ip-mac active 10.0.0.1 aaaa.bbbb.cccd 11gi6/4 ip-mac active deny-all deny-all 12-20This example shows the display when the interface has an IP source filter mode that is configured as IP MAC and an existing IP MAC binding 10.0.0.3/aaaa.bbbb.ccce on VLAN 10, but port security is not enabled on the interface:
Router# show ip verify source interface gigabitethernet6/5Interface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- -------------- ---------gi6/5 ip-mac active 10.0.0.3 permit-all 10gi6/5 ip-mac active deny-all permit-all 11-20This example shows the display when the interface does not have IP source filter mode configured:
Router# show ip verify source interface gigabitethernet6/6DHCP security is not configured on the interface gi6/6.This example shows how to display all the interfaces on the switch that have DHCP snooping security enabled:
Router# show ip verify sourceInterface Filter-type Filter-mode IP-address Mac-address Vlan--------- ----------- ----------- --------------- -------------- ---------gi6/1 ip active 10.0.0.1 10gi6/1 ip active deny-all 11-20gi6/2 ip inactive-trust-portgi6/3 ip inactive-no-snooping-vlangi6/4 ip-mac active 10.0.0.2 aaaa.bbbb.cccc 10gi6/4 ip-mac active 11.0.0.1 aaaa.bbbb.cccd 11gi6/4 ip-mac active deny-all deny-all 12-20gi6/5 ip-mac active 10.0.0.3 permit-all 10gi6/5 ip-mac active deny-all permit-all 11-20Router#This example shows how to display all the interfaces on the switch that have DHCP snooping security enabled:
Router# show ip verify source interface gi5/0/0 efp_id 10Interface Filter-type Filter-mode IP-address Mac-address Vlan EFP ID--------- ----------- ----------- --------------- ----------------- ---------- ----------Gi5/0/0 ip-mac active 123.1.1.1 00:0A:00:0A:00:0A 100 10Gi5/0/0 ip-mac active 123.1.1.2 00:0A:00:0A:00:0B 100 20Gi5/0/0 ip-mac active 123.1.1.3 00:0A:00:0A:00:0C 100 30Related Commands
term ip netmask-format
To specify the format in which netmasks are displayed in show command output, use the term ip netmask-format command in EXEC configuration mode. To restore the default display format, use the no form of this command.
term ip netmask-format {bitcount | decimal | hexadecimal}
no term ip netmask-format [bitcount | decimal | hexadecimal]
Syntax Description
bitcount
Number of bits in the netmask.
decimal
Netmask dotted decimal notation.
hexadecimal
Netmask hexadecimal format.
Defaults
Netmasks are displayed in dotted decimal format.
Command Modes
EXEC
Command History
Usage Guidelines
IP uses a 32-bit mask that indicates which address bits belong to the network and subnetwork fields, and which bits belong to the host field. This range of IP addresses is called a netmask. By default, show commands display an IP address and then its netmask in dotted decimal notation. For example, a subnet would be displayed as 131.108.11.55 255.255.255.0.
However, you can specify that the display of the network mask appear in hexadecimal format or bit count format instead. The hexadecimal format is commonly used on UNIX systems. The previous example would be displayed as 131.108.11.55 0XFFFFFF00.
The bitcount format for displaying network masks is to append a slash (/) and the total number of bits in the netmask to the address itself. The previous example would be displayed as 131.108.11.55/24.
Examples
The following example specifies that network masks for the session be displayed in bitcount notation in the output of show commands:
term ip netmask-format bitcount
