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Cisco IOS IP Command Reference, Volume 1 of 4: Addressing and Services, Release 12.3
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Introduction
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IP Addressing and Services Commands: A through C
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IP Addressing and Services Commands: D through H
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IP Addressing and Services Commands: idle through ip local-proxy-arp
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IP Addressing and Services Commands: ip mask-reply through ip web-cache
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IP Addressing and Services Commands: L through R
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IP Addressing and Services Commands: serverfarm through show ip nat
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IP Addressing and Services Commands: show ip nhrp through synguard
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IP Addressing and Services Commands: T through W
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Table Of Contents
show ip dhcp relay information trusted-sources
show ip dhcp server statistics
serverfarm
To associate a real server farm with a virtual server, use the serverfarm command in SLB virtual server configuration mode. To remove the server farm association from the virtual server configuration, use the no form of this command.
serverfarm serverfarm-name
no serverfarm
Syntax Description
serverfarm-name
Name of a server farm that has already been defined using the ip slb serverfarm command.
Defaults
No default behavior or values.
Command Modes
SLB virtual server configuration
Command History
12.0(7)XE
This command was introduced.
12.1(5)T
This command was integrated into Cisco IOS Release 12.1(5)T.
Examples
The following example shows how the ip slb vserver, virtual, and serverfarm commands are used to associate the real server farm named PUBLIC with the virtual server named PUBLIC_HTTP:
ip slb vserver PUBLIC_HTTPvirtual 10.0.0.1 tcp wwwserverfarm PUBLICRelated Commands
show ip slb vservers
Displays information about the virtual servers.
virtual
Configures the virtual server attributes.
service dhcp
To enable the Cisco IOS Dynamic Host Configuration Protocol (DHCP) server and relay agent features on your router, use the service dhcp command in global configuration mode. To disable the Cisco IOS DHCP server and relay agent features, use the no form of this command.
service dhcp
no service dhcp
Syntax Description
This command has no arguments or keywords.
Defaults
Enabled
Command Modes
Global configuration
Command History
Usage Guidelines
The BOOTP and DHCP servers in Cisco IOS software both use the ICMP port (port 67) by default. ICMP "port unreachable messages" will only be returned to the sender if both the BOOTP server and DHCP server are disabled. Disabling only one of the servers will not result in ICMP port unreachable messages.
Examples
The following example enables DHCP services on the DHCP server:
service dhcpshow access-lists
To display the contents of current access lists, use the show access-lists command in privileged EXEC mode.
show access-lists [access-list-number | access-list-name]
Syntax Description
access-list-number
(Optional) Number of the access list to display. The system displays all access lists by default.
access-list-name
(Optional) Name of the IP access list to display.
Defaults
The system displays all access lists.
Command Modes
Privileged EXEC
Command History
Examples
The following is sample output from the show access-lists command when access list 101 is specified:
Router# show access-lists 101Extended IP access list 101permit tcp host 198.92.32.130 any established (4304 matches) check=5permit udp host 198.92.32.130 any eq domain (129 matches)permit icmp host 198.92.32.130 anypermit tcp host 198.92.32.130 host 171.69.2.141 gt 1023permit tcp host 198.92.32.130 host 171.69.2.135 eq smtp (2 matches)permit tcp host 198.92.32.130 host 198.92.30.32 eq smtppermit tcp host 198.92.32.130 host 171.69.108.33 eq smtppermit udp host 198.92.32.130 host 171.68.225.190 eq syslogpermit udp host 198.92.32.130 host 171.68.225.126 eq syslogdeny ip 150.136.0.0 0.0.255.255 224.0.0.0 15.255.255.255deny ip 171.68.0.0 0.1.255.255 224.0.0.0 15.255.255.255 (2 matches) check=1deny ip 172.24.24.0 0.0.1.255 224.0.0.0 15.255.255.255deny ip 192.82.152.0 0.0.0.255 224.0.0.0 15.255.255.255deny ip 192.122.173.0 0.0.0.255 224.0.0.0 15.255.255.255deny ip 192.122.174.0 0.0.0.255 224.0.0.0 15.255.255.255deny ip 192.135.239.0 0.0.0.255 224.0.0.0 15.255.255.255deny ip 192.135.240.0 0.0.7.255 224.0.0.0 15.255.255.255deny ip 192.135.248.0 0.0.3.255 224.0.0.0 15.255.255.255An access list counter counts how many packets are allowed by each line of the access list. This number is displayed as the number of matches. Check denotes how many times a packet was compared to the access list but did not match.
The following is sample output from the show access-lists command when the Turbo Access Control List (ACL) feature is configured on all of the following access lists.
Note
The permit and deny information displayed by the show access-lists command may not be in the same order as that entered using the access-list command
Router# show access-listsStandard IP access list 1 (Compiled)deny anyStandard IP access list 2 (Compiled)deny 192.168.0.0, wildcard bits 0.0.0.255permit anyStandard IP access list 3 (Compiled)deny 0.0.0.0deny 192.168.0.1, wildcard bits 0.0.0.255permit anyStandard IP access list 4 (Compiled)permit 0.0.0.0permit 192.168.0.2, wildcard bits 0.0.0.255The following is sample output from the show access-lists command that shows information for IPv6 access lists when IPv6 is configured on the network:
Router# show access-listsIPv6 access list list2deny ipv6 FEC0:0:0:2::/64 any sequence 10permit ipv6 any any sequence 20For information on how to configure access lists, refer to the "Configuring IP Services" chapter of the Cisco IOS IP Configuration Guide.
For information on how to configure dynamic access lists, refer to the "Traffic Filtering and Firewalls" part of the Cisco IOS Security Configuration Guide.
Related Commands
show access-list compiled
To display a table showing Turbo Access Control Lists (ACLs), use the show access-list compiled command in EXEC mode.
show access-list compiled
Syntax Description
This command has no arguments or keywords.
Command Modes
User EXEC
Privileged EXECCommand History
12.0(6)S
This command was introduced.
12.1(1)E
This command was introduced for Cisco 7200 series routers.
12.1(5)T
This command was integrated into Cisco IOS
Release 12.1(5)T.
Usage Guidelines
This command is used to display the status and condition of the Turbo ACL tables associated with each access list. The memory usage is displayed for each table; large and complex access lists may require substantial amounts of memory. If the memory usage is greater than the memory available, you can disable the Turbo ACL feature so that memory exhaustion does not occur, but the acceleration of the access lists is not then enabled.
Examples
The following is partial sample output from the show access-list compiled command:
Router# show access-list compiledCompiled ACL statistics:12 ACLs loaded, 12 compiled tablesACL State Tables Entries Config Fragment Redundant Memory1 Operational 1 2 1 0 0 1Kb2 Operational 1 3 2 0 0 1Kb3 Operational 1 4 3 0 0 1Kb4 Operational 1 3 2 0 0 1Kb5 Operational 1 5 4 0 0 1Kb9 Operational 1 3 2 0 0 1Kb20 Operational 1 9 8 0 0 1Kb21 Operational 1 5 4 0 0 1Kb101 Operational 1 15 9 7 2 1Kb102 Operational 1 13 6 6 0 1Kb120 Operational 1 2 1 0 0 1Kb199 Operational 1 4 3 0 0 1KbFirst level lookup tables:Block Use Rows Columns Memory used0 TOS/Protocol 6/16 12/16 660481 IP Source (MS) 10/16 12/16 660482 IP Source (LS) 27/32 12/16 1320963 IP Dest (MS) 3/16 12/16 660484 IP Dest (LS) 9/16 12/16 660485 TCP/UDP Src Port 1/16 12/16 660486 TCP/UDP Dest Port 3/16 12/16 660487 TCP Flags/Fragment 3/16 12/16 66048Related Commands
show arp
To display the entries in the Address Resolution Protocol (ARP) table, use the show arp privileged EXEC command.
show arp
Syntax Description
This command has no arguments or keywords.
Command Modes
Privileged EXEC
Command History
Examples
The following is sample output from the show arp command:
Router# show arpProtocol Address Age (min) Hardware Addr Type InterfaceInternet 131.108.42.112 120 0000.a710.4baf ARPA Ethernet3AppleTalk 4028.5 29 0000.0c01.0e56 SNAP Ethernet2Internet 131.108.42.114 105 0000.a710.859b ARPA Ethernet3AppleTalk 4028.9 - 0000.0c02.a03c SNAP Ethernet2Internet 131.108.42.121 42 0000.a710.68cd ARPA Ethernet3Internet 131.108.36.9 - 0000.3080.6fd4 SNAP TokenRing0AppleTalk 4036.9 - 0000.3080.6fd4 SNAP TokenRing0Internet 131.108.33.9 - 0000.0c01.7bbd SNAP Fddi0Table 2 describes the significant fields shown in the display.
show glbp
To display Gateway Load Balancing Protocol (GLBP) information, use the show glbp command in privileged EXEC mode.
show glbp [interface-type interface-number] [group] [state] [brief]
Syntax Description
Command Modes
Privileged EXEC
Command History
12.2(14)S
This command was introduced.
12.2(15)T
This command was integrated into Cisco IOS Release 12.2(15)T.
Usage Guidelines
Use the show glbp command to display information about GLBP groups on a router. The brief keyword displays a single line of information about each virtual gateway or virtual forwarder.
Examples
The following is sample output from the show glbp command:
Router# show glbpFastEthernet0/0 - Group 10State is Active2 state changes, last state change 23:50:33Virtual IP address is 10.21.8.10Hello time 5 sec, hold time 18 secNext hello sent in 4.300 secsRedirect time 600 sec, forwarder time-out 7200 secAuthentication text "stringabc"Preemption enabled, min delay 60 secActive is localStandby is unknownPriority 254 (configured)Weighting 105 (configured 110), thresholds: lower 95, upper 105Track object 2 state Down decrement 5Load balancing: host-dependentThere is 1 forwarder (1 active)Forwarder 1State is Active1 state change, last state change 23:50:15MAC address is 0007.b400.0101 (default)Owner ID is 0005.0050.6c08Redirection enabledPreemption enabled, min delay 60 secActive is local, weighting 105The following is sample output from the show glbp command with the brief keyword specified:
Router# show glbp briefInterface Grp Fwd Pri State Address Active router Standby routerFa0/0 10 - 254 Active 10.21.8.10 local unknownFa0/0 10 1 7 Active 0007.b400.0101 local -Table 3 describes the significant fields shown in the displays.
Related 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 host names and addresses, use the show hosts command in EXEC mode.
show hosts
Syntax Description
This command has no arguments or keywords.
Command Modes
EXEC
Command History
10.0
This command was introduced.
12.2(4)T
This command was updated to support the Cisco modem user interface feature.
Examples
The following is sample output from the show hosts command:
Router# show hostsDefault domain is CISCO.COMName/address lookup uses domain serviceName servers are 255.255.255.255Host Flag Age Type Address(es)SLAG.CISCO.COM (temp, OK) 1 IP 172.20.4.10CHAR.CISCO.COM (temp, OK) 8 IP 192.168.7.50CHAOS.CISCO.COM (temp, OK) 8 IP 172.20.1.115DIRT.CISCO.COM (temp, EX) 8 IP 172.20.1.111DUSTBIN.CISCO.COM (temp, EX) 0 IP 172.20.1.27DREGS.CISCO.COM (temp, EX) 24 IP 172.20.1.30Table 4 describes the significant fields shown in the display.
The following is sample output from a router when a modem telephone number is mapped to an IP host address for the Cisco modem user interface feature using the ip host global configuration command:
Router# show hostsDefault domain is not setName/address lookup uses domain serviceName servers are 255.255.255.255Codes: u - unknown, e - expired, * - OK, ? - revalidatet - temporary, p - permanentHost Age Type Address(es)*p p4085554567 0 IP 1.2.1.6*p t4085551234 0 IP 1.2.1.5Under the Host field, a "p" preceding the number indicates a pulse-dialed modem telephone number, and a "t" indicates a tone-dialed modem telephone number. The IP address mapped to the telephone number appears under the Address(es) field. See Table 4 for descriptions of the other fields seen in this display.
Related Commands
clear arp interface
Deletes entries from the host name-to-address cache.
ip helper-address
Defines a static host-name-to-address mapping in the host cache.
show interface mac
To display MAC accounting information for interfaces configured for MAC accounting, use the show interface mac command in user EXEC or privileged EXEC mode.
show interface [type number] mac
Syntax Description
Command Modes
User EXEC
Privileged EXECCommand History
Usage Guidelines
The show interface mac command displays information for one interface, when specified, or all interfaces configured for MAC accounting.
For incoming packets on the interface, the accounting statistics are gathered before the committed access rate (CAR)/distributed committed access rate (DCAR) functionality is performed on the packet. For outgoing packets on the interface, the accounting statistics are gathered after the CAR output, and before DCAR output or distributed weighted random early detection (DWRED) or distributed weighted fair queuing (DWFQ) functionality is performed on the packet.
Therefore, if DCAR or DWRED is performed on the interface and packets are dropped, the dropped packets are still counted in the show interface mac command.
The maximum number of MAC addresses that can be stored for the input and output addresses is 512 each. After the maximum is reached, subsequent MAC addresses are ignored.
To clear the accounting statistics, use the clear counter EXEC command. To configure an interface for IP accounting based on the MAC address, use the ip accounting mac-address interface configuration command.
Examples
The following is sample output from the show interface mac command:
Router# show interface ethernet 0/1/1 macEthernet0/1/1Input (511 free)0007.f618.4449(228): 4 packets, 456 bytes, last: 2684ms agoTotal: 4 packets, 456 bytesOutput (511 free)0007.f618.4449(228): 4 packets, 456 bytes, last: 2692ms agoTotal: 4 packets, 456 bytesTable 5 describes the significant fields shown in the display.
Related Commands
ip accounting mac-address
Enables IP accounting on any interface based on the source and destination MAC address.
show interface precedence
To display precedence accounting information for interfaces configured for precedence accounting, use the show interface precedence command in user EXEC or privileged EXEC mode.
show interface [type number] precedence
Syntax Description
Command Modes
User EXEC
Privileged EXECCommand History
Usage Guidelines
The show interface precedence command displays information for one interface, when specified, or all interfaces configured for IP precedence accounting.
For incoming packets on the interface, the accounting statistics are gathered before the committed access rate (CAR)/distributed committed access rate (DCAR) functionality is performed on the packet. For outgoing packets on the interface, the accounting statistics are gathered after the CAR output, and before DCAR output or distributed weighted random early detection (DWRED) or distributed weighted fair queuing (DWFQ) functionality is performed on the packet. Therefore, if DCAR or DWRED is performed on the interface and packets are dropped, the dropped packets are still counted in the show interface mac command.
To clear the accounting statistics, use the clear counter EXEC command.
To configure an interface for IP accounting based on IP precedence, use the ip accounting precedence interface configuration command.
Examples
The following is sample output from the show interface precedence command. In this example, the total packet and byte counts are calculated for the interface that receives (input) or sends (output) IP packets and sorts the results based on IP precedence.
Router# show interface ethernet 0/1/1 precedenceEthernet0/1/1InputPrecedence 0: 4 packets, 456 bytesOutputPrecedence 0: 4 packets, 456 bytesTable 6 describes the fields shown in the display.
Related Commands
ip accounting precedence
Enables IP accounting on any interface based on IP precedence.
show ip access-list
To display the contents of all current IP access lists, use the show ip access-list command in user EXEC or privileged EXEC mode.
show ip access-list [access-list-number | access-list-name]
Syntax Description
access-list-number
(Optional) Number of the IP access list to display.
access-list-name
(Optional) Name of the IP access list to display.
Defaults
Displays all standard and extended IP access lists.
Command Modes
User EXEC
Privileged EXECCommand History
Usage Guidelines
The show ip access-list command provides output identical to the show access-lists command, except that it is IP-specific and allows you to specify a particular access list.
Examples
The following is sample output from the show ip access-list command when all access lists are requested:
Router# show ip access-listExtended IP access list 101deny udp any any eq ntppermit tcp any anypermit udp any any eq tftppermit icmp any anypermit udp any any eq domainThe following is sample output from the show ip access-list command when the name of a specific access list is requested:
Router# show ip access-list InternetfilterExtended IP access list Internetfilterpermit tcp any 171.69.0.0 0.0.255.255 eq telnetdeny tcp any anydeny udp any 171.69.0.0 0.0.255.255 lt 1024deny ip any any logshow ip accounting
To display the active accounting or checkpointed database or to display access list violations, use the show ip accounting command in user EXEC or privileged EXEC mode.
show ip accounting [checkpoint] [output-packets | access-violations]
Syntax Description
Defaults
If neither the output-packets nor access-violations keyword is specified, the show ip accounting command displays information pertaining to packets that passed access control and were routed.
Command Modes
User EXEC
Privileged EXECCommand History
10.0
This command was introduced.
10.3
The output-packets and access-violations keywords were added.
Usage Guidelines
If you do not specify any keywords, the show ip accounting command displays information about the active accounting database, and traffic coming from a remote site and transiting through a router.
To display IP access violations, you must use the access-violations keyword. If you do not specify the keyword, the command defaults to displaying the number of packets that have passed access lists and were routed.
To use this command, you must first enable IP accounting on a per-interface basis.
Examples
The following is sample output from the show ip accounting command:
Router# show ip accountingSource Destination Packets Bytes172.16.19.40 192.168.67.20 7 306172.16.13.55 192.168.67.20 67 2749172.16.2.50 192.168.33.51 17 1111172.16.2.50 172.31.2.1 5 319172.16.2.50 172.31.1.2 463 30991172.16.19.40 172.16.2.1 4 262172.16.19.40 172.16.1.2 28 2552172.16.20.2 172.16.6.100 39 2184172.16.13.55 172.16.1.2 35 3020172.16.19.40 192.168.33.51 1986 95091172.16.2.50 192.168.67.20 233 14908172.16.13.28 192.168.67.53 390 24817172.16.13.55 192.168.33.51 214669 9806659172.16.13.111 172.16.6.23 27739 1126607172.16.13.44 192.168.33.51 35412 1523980192.168.7.21 172.163.1.2 11 824172.16.13.28 192.168.33.2 21 1762172.16.2.166 192.168.7.130 797 141054172.16.3.11 192.168.67.53 4 246192.168.7.21 192.168.33.51 15696 695635192.168.7.24 192.168.67.20 21 916172.16.13.111 172.16.10.1 16 1137accounting threshold exceeded for 7 packets and 433 bytesThe following is sample output from the show ip accounting access-violations command. The output pertains to packets that failed access lists and were not routed:
Router# show ip accounting access-violationsSource Destination Packets Bytes ACL172.16.19.40 192.168.67.20 7 306 77172.16.13.55 192.168.67.20 67 2749 185172.16.2.50 192.168.33.51 17 1111 140172.16.2.50 172.16.2.1 5 319 140172.16.19.40 172.16.2.1 4 262 77Accounting data age is 41The following is sample output from the show ip accounting command. The output shows the original source and destination addresses that are separated by three routers:
Router3# show ip accountingSource Destination Packets Bytes10.225.231.154 172.16.10.2 44 2816010.76.97.34 172.16.10.2 44 2816010.10.11.1 172.16.10.2 507 32448010.10.10.1 172.16.10.2 507 31839610.100.45.1 172.16.10.2 508 32512010.98.32.5 172.16.10.2 44 28160Accounting data age is 2Table 7 describes the significant fields shown in the displays.
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 similarly to aliases, use the show ip aliases EXEC command.
show ip aliases
Syntax Description
This command has no arguments or keywords.
Command Modes
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.
Examples
The following is sample output from the show ip aliases command:
Router# show ip aliasesIP Address Port172.16.0.0 SLIP TTY1The display lists the IP address and corresponding port number.
Related Commands
show ip arp
To display the Address Resolution Protocol (ARP) cache, where Serial Line Internet Protocol (SLIP) addresses appear as permanent ARP table entries, use the show ip arp EXEC command.
show ip arp [ip-address] [host-name] [mac-address] [interface type number]
Syntax Description
Command Modes
EXEC
Command History
Usage Guidelines
ARP establishes correspondences between network addresses (an IP address, for example) and LAN hardware addresses (Ethernet addresses). A record of each correspondence is kept in a cache for a predetermined amount of time and then discarded.
Examples
The following is sample output from the show ip arp command:
Router# show ip arpProtocol Address Age(min) Hardware Addr Type InterfaceInternet 172.16.233.22 9 0000.0c59.f892 ARPA Ethernet0/0Internet 172.16.233.21 8 0000.0c07.ac00 ARPA Ethernet0/0Internet 172.16.233.19 - 0000.0c63.1300 ARPA Ethernet0/0Internet 172.16.233.30 9 0000.0c36.6965 ARPA Ethernet0/0Internet 172.16.168.11 - 0000.0c63.1300 ARPA Ethernet0/0Internet 172.16.168.254 9 0000.0c36.6965 ARPA Ethernet0/0Table 8 describes the significant fields shown in the display.
show ip casa affinities
To display statistics about affinities, use the show ip casa affinities command in user EXEC or privileged EXEC mode.
show ip casa affinities [stats] | [saddr ip-address [detail]] | [daddr ip-address [detail]] | sport source-port [detail]] | dport destination-port [detail]] | protocol protocol [detail]]
