Table Of Contents
ip rip authentication key-chain
RIP Commands
Use the commands in this chapter to configure and monitor Routing Information Protocol (RIP). For RIP configuration information and examples, refer to the "Configuring RIP" chapter of the Network Protocols Configuration Guide, Part 1.
auto-summary
To restore the default behavior of automatic summarization of subnet routes into network-level routes, use the auto-summary router configuration command. To disable this feature and transmit subprefix routing information across classful network boundaries, use the no form of this command.
auto-summary
no auto-summarySyntax Description
This command has no arguments or keywords.
Default
Enabled (the software summarizes subprefixes to the classful network boundary when crossing classful network boundaries).
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Route summarization reduces the amount of routing information in the routing tables.
RIP Version 1 always uses automatic summarization. If you are using RIP Version 2, you can turn off automatic summarization by specifying no auto-summary. Disable automatic summarization if you must perform routing between disconnected subnets. When automatic summarization is off, subnets are advertised.
Example
In the following example, network numbers are not summarized automatically:
router ripversion 2no auto-summarydefault-information originate
To generate a default route into RIP, use the default-information originate router configuration command. To disable this feature, use the no form of this command.
default-information originate [route-map mapname]
no default-information originateSyntax Description
route-map mapname
(Optional) Routing process will generate the default route if the route map is satisfied.
Default
Disabled
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Example
The following example originates a default route (0.0.0.0/0) over a certain interface when 172.68.0.0/16 is present. This is called "conditional default origination."
router ripversion 2network 172.68.16.0default-information originate route-map condition!route-map condition permit 10match ip address 10set interface s1/0!access-list 10 permit 172.68.16.0 0.0.0.255!default-metric
To set default metric values for RIP, use this form of the default-metric router configuration command. To return to the default state, use the no form of this command.
default-metric number
no default-metric [number]Syntax Description
Default
Built-in, automatic metric translations, as appropriate for each routing protocol
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The default-metric command is used in conjunction with the redistribute router configuration command to cause the current routing protocol to use the same metric value for all redistributed routes. A default metric helps solve the problem of redistributing routes with incompatible metrics. Whenever metrics do not convert, using a default metric provides a reasonable substitute and enables the redistribution to proceed.
Example
The following example shows a router in autonomous system 109 using both the RIP and the OSPF routing protocols. The example advertises OSPF-derived routes using the RIP protocol and assigns the OSPF-derived routes a RIP metric of 10.
router ripdefault-metric 10redistribute ospf 109Related Commands
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redistribute
ip rip authentication key-chain
To enable authentication for RIP Version 2 packets and to specify the set of keys that can be used on an interface, use the ip rip authentication key-chain interface configuration command. Use the no form of this command to prevent authentication.
ip rip authentication key-chain name-of-chain
no ip rip authentication key-chain [name-of-chain]Syntax Description
Default
No authentication is provided for RIP packets.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
If no key chain is configured with the key-chain command, no authentication is performed on the interface (not even the default authentication).
Example
The following example configures the interface to accept and send any key belonging to the key chain named trees:
ip rip authentication key-chain treesRelated Commands
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key chain
ip rip authentication mode
To specify the type of authentication used in RIP Version 2 packets, use the ip rip authentication mode interface configuration command. Use the no form of this command to restore clear text authentication.
ip rip authentication mode {text | md5}
no ip rip authentication modeSyntax Description
Default
Clear text authentication is provided for RIP packets.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
RIP Version 1 does not support authentication.
Example
The following example configures the interface to use MD5 authentication:
ip rip authentication mode md5Related Commands
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ip rip authentication key-chain
key chainip rip receive version
To specify a RIP version to receive on an interface basis, use the ip rip receive version interface configuration command. Use the no form of this command to follow the global version rules.
ip rip receive version [1] [2]
no ip rip receive versionSyntax Description
1
(Optional) Accepts only RIP Version 1 packets on the interface.
2
(Optional) Accepts only RIP Version 2 packets on the interface.
Default
The software behaves according to the version command.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Use this command to override the default behavior of RIP as specified by the version command. This command applies only to the interface being configured. You can configure the interface to accept both RIP versions.
Examples
The following example configures the interface to receive both RIP Version 1 and Version 2 packets:
ip rip receive version 1 2The following example configures the interface to receive only RIP Version 1 packets:
ip rip receive version 1Related Commands
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ip rip send version
To specify a RIP version to send on an interface basis, use the ip rip send version interface configuration command. Use the no form of this command to follow the global version rules.
ip rip send version [1] [2]
no ip rip send versionSyntax Description
1
(Optional) Sends only RIP Version 1 packets out the interface.
2
(Optional) Sends only RIP Version 2 packets out the interface.
Default
The software behaves according to the router version command.
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
Use this command to override the default behavior of RIP as specified by the router version command. This command applies only to the interface being configured.
Examples
The following example configures the interface to send both RIP Version 1 and Version 2 packets out the interface:
ip rip send version 1 2The following example configures the interface to send only RIP Version 2 packets out the interface:
ip rip send version 2Related Commands
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ip split-horizon
To enable the split horizon mechanism, use the ip split-horizon interface configuration command. To disable the split horizon mechanism, use the no form of this command.
ip split-horizon
no ip split-horizonSyntax Description
This command has no arguments or keywords.
Default
Varies with media
Command Mode
Interface configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
For all interfaces except those for which either Frame Relay or SMDS encapsulation is enabled, the default condition for this command is ip split-horizon; in other words, the split horizon feature is active. If the interface configuration includes either the encapsulation frame-relay or encapsulation smds commands, then the default is for split horizon to be disabled. Split horizon is not disabled by default for interfaces using any of the X.25 encapsulations.
Note
For networks that include links over X.25 PSNs, the neighbor router configuration command can be used to defeat the split horizon feature. You can as an alternative explicitly specify the no ip split-horizon command in your configuration. However, if you do so you must similarly disable split horizon for all routers in any relevant multicast groups on that network.
If split horizon has been disabled on an interface and you wish to enable it, use the ip split-horizon command to restore the split horizon mechanism.
Note
Example
The following simple example disables split horizon on a serial link. The serial link is connected to an X.25 network:
interface serial 0encapsulation x25no ip split-horizonRelated Commands
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neighbor
neighbor (IGRP and RIP)
To define a neighboring router with which to exchange routing information, use this form of the neighbor router configuration command. To remove an entry, use the no form of this command.
neighbor ip-address
no neighbor ip-addressSyntax Description
Default
No neighboring routers are defined.
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command permits the point-to-point (nonbroadcast) exchange of routing information. When used in combination with the passive-interface router configuration command, routing information can be exchanged between a subset of routers and access servers on a LAN.
Multiple neighbor commands can be used to specify additional neighbors or peers.
Example
In the following example, RIP updates are sent to all interfaces on network 131.108.0.0 except interface Ethernet 1. However, in this case a neighbor router configuration command is included. This command permits the sending of routing updates to specific neighbors. One copy of the routing update is generated per neighbor.
router ripnetwork 131.108.0.0passive-interface ethernet 1neighbor 131.108.20.4Related Commands
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passive-interface
network (RIP)
To specify a list of networks for the Routing Information Protocol (RIP) routing process, use this form of the network router configuration command. To remove an entry, use the no form of this command.
network network-number
no network network-numberSyntax Description
Default
No networks are specified.
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The network number specified must not contain any subnet information.There is no limit to the number of network commands used on the router. RIP routing updates will be sent and received only through interfaces on this network.
RIP sends updates to the interfaces in the specified networks. Also, if an interface's network is not specified, it will not be advertised in any RIP update.
Example
The following example defines RIP as the routing protocol to be used on all interfaces connected to networks 128.99.0.0 and 192.31.7.0:
router ripnetwork 128.99.0.0network 192.31.7.0Related Commands
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offset-list
To add an offset to incoming and outgoing metrics to routes learned via RIP, use the offset-list router configuration command. To remove an offset list, use the no form of this command.
offset-list {access-list-number | name} {in | out} offset [type number]
no offset-list {access-list-number | name} {in | out} offset [type number]Syntax Description
Default
Disabled
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0. The type and number arguments first appeared in Cisco IOS Release 10.3. The name argument first appeared in Cisco IOS Release 11.2.
The offset value is added to the routing metric. An offset-list with an interface type and interface number is considered extended and takes precedence over an offset-list that is not extended. Therefore, if an entry passes the extended offset-list and the normal offset-list, the extended offset-list's offset is added to the metric.
Examples
In the following example, the router applies an offset of 10 to the router's delay component only to access list 21:
offset-list 21 out 10In the following example, the router applies an offset of 10 to routes learned from Ethernet interface 0:
offset-list 21 in 10 ethernet 0output-delay
To change the interpacket delay for RIP updates sent, use the output-delay router configuration command. To remove the delay, use the no form of this command.
output-delay delay
no output-delay [delay]Syntax Description
delay
Delay, in milliseconds, between packets in a multiple-packet RIP update. The range is 8 to 50 milliseconds. The default is no delay.
Default
0 milliseconds
Command Mode
Router configuration
Usage Guidelines
Consider using this command if you have a high-end router sending at high speed to a low-speed router that might not be able to receive at that fast a rate. Configuring this command will help prevent the routing table from losing information.
Example
In the following example, the interpacket delay is set to 10 milliseconds:
output-delay 10router rip
To configure the Routing Information Protocol (RIP) routing process, use the router rip global configuration command. To turn off the RIP routing process, use the no form of this command.
router rip
no router ripSyntax Description
This command has no arguments or keywords.
Default
No RIP routing process is defined.
Command Mode
Global configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
Example
The following example shows how to begin the RIP routing process:
router ripRelated Commands
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timers basic
To adjust RIP network timers, use the timers basic router configuration command. To restore the default timers, use the no form of this command.
timers basic update invalid holddown flush
no timers basicSyntax Description
Defaults
update is 30 seconds
invalid is 180 seconds
holddown is 180 seconds
flush is 240 secondsCommand Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
The basic timing parameters for RIP are adjustable. Since RIP is executing a distributed, asynchronous routing algorithm, it is important that these timers be the same for all routers and access servers in the network.
Note
Example
In the following example, updates are broadcast every 5 seconds. If a router is not heard from in 15 seconds, the route is declared unusable. Further information is suppressed for an additional 15 seconds. At the end of the suppression period, the route is flushed from the routing table.
router riptimers basic 5 15 15 30Note that by setting a short update period, you run the risk of congesting slow-speed serial lines; however, this is not a big concern on faster-speed Ethernets and T1-rate serial lines. Also, if you have many routes in your updates, you can cause the routers to spend an excessive amount of time processing updates.
validate-update-source
To have the Cisco IOS software validate the source IP address of incoming routing updates for RIP and IGRP routing protocols, use the validate-update-source router configuration command. To disable this function, use the no form of this command.
validate-update-source
no validate-update-sourceSyntax Description
This command has no arguments or keywords.
Default
Enabled
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 10.0.
This command is only applicable to RIP and IGRP. The software ensures that the source IP address of incoming routing updates is on the same IP network as one of the addresses defined for the receiving interface.
Disabling split horizon on the incoming interface will also cause the system to perform this validation check.
For unnumbered IP interfaces (interfaces configured as ip unnumbered), no checking is performed.
Example
In the following example, a router is configured to not perform validation checks on the source IP address of incoming RIP updates:
router ripnetwork 128.105.0.0no validate-update-sourceversion
To specify a RIP version used globally by the router, use the version router configuration command. Use the no form of this command to restore the default value.
version {1 | 2}
no versionSyntax Description
Default
The software receives RIP Version 1 and Version 2 packets, but sends only Version 1 packets.
Command Mode
Router configuration
Usage Guidelines
This command first appeared in Cisco IOS Release 11.1.
To specify RIP versions used on an interface basis, use the ip rip receive version and ip rip send version commands.
Example
The following example enables the software to send and receive RIP Version 2 packets:
version 2Related Commands
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ip rip receive version
ip rip send version
show ip protocols
