Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 227)

To configure a RIP neighbor filters, enter the neighbor command.
device(config-rip-router)# neighbor 1 deny any
This command configures the Brocade device so that the device does not learn any RIP routes from
any RIP neighbors.
Syntax: [no] neighbor filter-num {permit | deny} {source-ip-address | any}
The following commands configure the Brocade device to learn routes from all neighbors except
10.70.12.104. Once you define a RIP neighbor filter, the default action changes from learning all routes
from all neighbors to denying all routes from all neighbors except the ones you explicitly permit. Thus, to
deny learning from a specific neighbor but allow all other neighbors, you must add a filter that allows
learning from all neighbors. Make sure you add the filter to permit all neighbors as the last filter (the one
with the highest filter number). Otherwise, the software can match on the permit all filter before a filter
that denies a specific neighbor, and learn routes from that neighbor.
device(config-rip-router)# neighbor 2 deny 10.70.12.104
device(config-rip-router)# neighbor 1024 permit any
Changing the route loop prevention method
RIP uses the following methods to prevent routing loops:
• Split horizon - The device does not advertise a route on the same interface as the one on which the
Brocade device learned the route. This is the default.
• Poison reverse - The device assigns a cost of 16 ("infinite" or "unreachable") to a route before
advertising it on the same interface as the one on which the Brocade device learned the route.
These loop prevention methods are configurable on a global basis as well as on an individual interface
basis. One of the methods is always in effect on an interface enabled for RIP. Thus, if you disable one
method, the other method is enabled.
NOTE
These methods are in addition to RIP’s maximum valid route cost of 15.
To disable poison reverse and enable split horizon on a global basis, enter the following command.
device(config-rip-router)# no poison-reverse
Syntax: [no] poison-reverse
To disable poison reverse and enable split horizon on an interface, enter commands such as the
following.
device(config)#interface ethernet 1/1/1
device(config-if-e10000-1/1/1)# no ip rip poison-reverse
Syntax: [no] ip rip poison-reverse
To disable split horizon and enable poison reverse on an interface, enter commands such as the
following.
device(config)#interface ethernet 1/1/1
device(config-if-e10000-1/1/1)# ip rip poison-reverse
You can configure the Brocade device to avoid routing loops by advertising local RIP routes with a cost
of 16 ("infinite" or "unreachable") when these routes go down.
device(config-rip-router)# poison-local-routes
Changing the route loop prevention method
FastIron Ethernet Switch Layer 3 Routing Configuration Guide 227
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