Advanced Configuration of RIP

Disabling Route Summarization

RIP Version 1 always uses automatic route summarization. You cannot disable this feature for RIP Version 1. RIP Version 2 uses automatic route summarization by default. The RIP routing process summarizes on network number boundaries. This can cause routing problems if you have non-contiguous networks.

For example, if you have a router with the networks 192.168.1.0, 192.168.2.0, and 192.168.3.0 connected to it, and those networks all participate in RIP, the RIP routing process creates the summary address 192.168.0.0 for those routes. If an additional router is added to the network with the networks 192.168.10.0 and 192.168.11.0, and those networks participate in RIP, they will also be summarized as 192.168.0.0. To prevent the possibility of traffic being routed to the wrong location, you should disable automatic route summarization on the routers creating the conflicting summary addresses.

To disable automatic router summarization, enter the following command in router configuration mode for the RIP routing process:

Detailed Steps

	Command	Purpose
Step 1	router rip Example: hostname(config)# router rip	This starts the RIP routing process and places you in router configuration mode.
Step 2	no auto-summarize Example: hostname(config-router):# no  auto-summarize	This step disables automatic route summarization.

Filtering Networks in RIP

To filter the networks received in updates, perform the following steps:

Detailed Steps

	Command	Purpose
Step 1	router rip Example: hostname(config)# router rip	This starts the RIP routing process and places you in router configuration mode.
Step 2	distribute-list acl in [interface if_name] distribute-list acl out [connected | eigrp  | interface if_name | ospf | rip | static] Example: hostname(config-router)# distribute-list acl2 in [interface interface1] hostname(config-router): distribute-list acl3 out [connected]	This step filters the networks sent in updates. You can specify an interface to apply the filter to only those updates received or sent by that interface. You can enter this command for each interface you want to apply a filter to. If you do not specify an interface name, the filter is applied to all RIP updates.

Redistributing Routes into the RIP Routing Process

You can redistribute routes from the OSPF, EIGRP, static, and connected routing processes into the RIP routing process.

To redistribute a routes into the RIP routing process, perform the following steps:

Detailed Steps

	Command	Purpose
Step 1	Do one of the following to redistribute the selected route type into the RIP routing process. You must specify the RIP metric values in the redistribute command if you do not have a default-metriccommand in the RIP router configuration.
	redistribute connected [ metric  <metric-value> | transparent ] [route-map  <route-map-name>] Example: hostname(config-router): # redistribute  connected [ metric <metric-value> |  transparent ] [route-map <route-map-name>]	Use this step to redistribute connected routes into the RIP routing process.
	redistribute static [metric {metric_value | transparent}] [route-map map_name] Example: hostname(config-router):# redistribute static [metric {metric_value |  transparent}] [route-map map_name]	Use this step to redistribute static routes into the EIGRP routing process.
	redistribute ospf pid [match {internal |  external [1 | 2] | nssa-external [1 | 2]}]  metric {metric_value | transparent}]  route-map map_name] Example: hostname(config-router):# redistribute  ospf pid [match {internal | external [1 |  2] | nssa-external [1 | 2]}] [metric  {metric_value | transparent}] [route-map map_name]	Use this step to redistribute routes from an OSPF routing process into the RIP routing process.
	redistribute eigrp as-num [metric  {metric_value | transparent}] [route-map  map_name] Example: hostname(config-router):# redistribute  eigrp as-num [metric {metric_value |  transparent}] [route-map map_name]	Use this step to redistribute routes from an EIGRP routing process into the RIP routing process.

Configuring RIP Send/Receive Version on an Interface

You can override the globally-set version of RIP the ASA uses to send and receive RIP updates on a per-interface basis.

To configure the RIP send and receive version, perform the following steps:

Detailed Steps

	Command	Purpose
Step 1	interface phy_if Example: hostname(config)# interface phy_if	This step enters interface configuration mode for the interface you are configuring.
Step 2	Do one of the following to to send or receive RIP updates on a per-interface basis.
	rip send version {[1] [2]} Example: hostname(config-if)# rip send version 1	This step specifies the version of RIP to use when sending RIP updates out of the interface. In this example, version 1 is selected.
	rip receive version {[1] [2]} Example: hostname(config-if)# rip receive version 2	This step specifies the version of RIP advertisements permitted to be received by an interface. In this example, version 2 is selected. RIP updates received on the interface that do not match the allowed version are dropped.

Enabling RIP Authentication

RIP route authentication provides MD5 authentication of routing updates from the RIP routing protocol. The MD5 keyed digest in each RIP packet prevents the introduction of unauthorized or false routing messages from unapproved sources.

RIP route authentication is configured on a per-interface basis. All RIP neighbors on interfaces configured for RIP message authentication must be configured with the same authentication mode and key for adjacencies to be established.

     To enable RIP authentication on an interface, perform the following steps:

Detailed Steps

	Command	Purpose
Step 1	router rip Example: hostname(config)# router rip	This creates an RIP routing process, and the user enters router configuration mode for this RIP process. The as-num argument is the autonomous system number of the RIP routing process.
Step 2	interface phy_if Example: hostname(config)# interface phy_if	Enter interface configuration mode for the interface on which you are configuring RIP message authentication.
Step 3	rip authentication mode {text | md5} Example: hostname(config-if)# rip authentication mode md5	This step sets the authentication mode. By default, text authentication is used. We recommend MD5 authentication.
Step 4	rip authentication key key key-id key-id Example: hostname(config-if)# rip authentication  key cisco key-id 200	Configure the authentication key used by the MD5 algorithm. The key argument can contain up to 16 characters. The key-id argument is a number from 0 to 255.

Monitoring RIP

You can use the following commands to monitor or debug the RIP routing process.

We recommend that you only use the debug commands to troubleshoot specific problems or during troubleshooting sessions with Cisco TAC.

Debugging output is assigned high priority in the CPU process and can render the system unusable. It is best to use debug commands during periods of lower network traffic and fewer users. Debugging during these periods decreases the likelihood that increased debug command processing overhead will affect system performance. For examples and descriptions of the command output, see the Cisco Security Appliance Command Reference.

To monitor or debug various RIP routing statistics, perform one of the following tasks:

Command	Purpose
Monitoring RIP Routing
show rip database	Display the contents of the RIP routing database.
show running-config router rip	Displays the RIP commands.
Debug RIP
debug rip events	Displays RIP processing events.
debug rip database	Displays RIP database events.

Configuration Example for RIP

The following example shows how to enable and configure RIP with various optional processes:

---

Step 1 Enable RIP:

hostname(config)# router rip 2

Step 2 Configure a default route into RIP:

hostname(config-router): default-information originate

Step 3 Specify the version of RIP to use:

hostname(config-router): version [1]

Step 4 Specify the interfaces that will participate in the RIP routing process:

hostname(config-router)# network 225.25.25.225

Step 5 Specify an interface to operate in passive mode:

hostname(config-router)# passive-interface [default]

Step 6 Redistribute a connected route into the RIP routing process

hostname(config-router): redistribute connected [metric bandwidth delay reliability 

Loading mtu] [route-map map_name]

Feature History for RIP

Table 22-1 lists the release history for this feature.

Table 22-1 Feature History for RIP

Feature Name	Releases	Feature Information
router rip	7.0	This feature allows you to route data, perform authentication, redistribute and monitor routing information, using the Routing Information Protocol (RIP) routing protocol. a