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Cisco ASA 5500 Series Configuration Guide using ASDM
Chapter28 Configuring RIP
Customizing RIP
The RIP routing process summarizes on network number boundaries, which can cause routing problems
if you have noncontiguous 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 that are creating conflicting summary addresses.
Because RIP Version 1 always uses automatic route summarization, and RIP Version 2 always uses
automatic route summarization by default, when configuring automatic route summarization, you only
need to disable it.
In ASDM, you can enable or disable automatic route summarization in a RIP process by performing the
following steps:
Step1 In the main ASDM window, choose Configuration > Device Setup > Routing > RIP > Setup.
Step2 Check the Enable RIP routing check box, and click Apply.
Step3 Check the Enable Auto-Summarization check box.
Uncheck this check box to disable automatic route summarization. Check this check box to reenable
automatic route summarization. RIP Version 1 always uses automatic summarization. You cannot disable
automatic route summarization for RIP Version 1. If you are using RIP Version 2, you can turn off
automatic route summarization by unchecking this check box. Disable automatic route summarization if
you must perform routing between disconnected subnets. When automatic route summarization is
disabled, subnets are advertised.
Step4 Click Apply.
Filtering Networks in RIP
To filter the networks received in updates, perform the following steps:
Note Before you begin, you must create a standard access list that permits the networks that you want the RIP
process to allow in the routing table and denies the networks that you want the RIP process to discard.
In ASDM, you can configure filter rules that allow you to filter the network received in RIP routing
updates or sent in RIP routing updates. Each filter rule consists of one or more network rules.
Step1 In the main ASDM window, choose Configuration > Device Setup > Routing > RIP > Setup.
Step2 Check the Enable RIP routing check box, and click Apply.
Step3 Choose Configuration > Device Setup > Routing > RIP > Filter Rules.
Step4 Click Add or Edit.
The Add or Edit Filter Rule dialog box appears, which allows you to create or edit filter rules that apply
to all interfaces or to a specific interface.
Step5 From the Direction drop-down list, choose the direction in which the filter should act.