Route filtering using Distribute List

What is Distribute List?
Distribute List is Like an access-list, use to deny or permit the routing update to pass through a router/interface.  Distribute List allow you apply an access list to a routing updates.
How to apply a Distribute List:
It can be apply on in or out bond of an interface under a routing process.
e.g in fig. R1 want to send a routing update to it neighbor, this update will go through from interface S0/0, router will check, is there some Distribute List apply to this interface. If there is a Distribute List which would contain the allow route to pass through this interface. In this list u may block, etc.
Distribute List Configuration in GNS3:

Here in figure you can see a two routing domain. R2, R3 and R4 running “ospf area 1”
R1 have some RIP routes which are\24 to\24.

Objective1: some of networks behind the R1, we don’t want to get out the entire network., remain in this networks not accessed from R4.

Objective2: But other two networks\24 &\24 can’t cross from rip-network. They remains in RIP network, can’t go across the R3 & R4.

Note: For full Lab configuration you can visit Route redistribution configuration.

Create an Access-list
R1(config)# ip access-list standard route_filter
R1(config-)#Permit any

Apply distribute list under routing process using that acces-list
R1(config-router)#Distrib-list route_filter out serial 0\2
R2#clrear ip route *
R2#Show ip route
From above configuration objective1 is achieved. You can view the figure that in R4 routing table there are not\24 &\24

For achieving the 2nd objective we need to do the same above steps and configurations. i.e.

R2(config)# Ip access-list standard route_filter2
R2(config)#Permit any
R2(config)#Router osfp 1
R2(config-router)#Distrib-list route_filter 2out rip

After completing above configuration you shall see that networks\24 &\24 disappear from R4’s routing table, but remains in R2 routing table.     


  1. I love it. However I did not see any interface Distrib-list route_filter out serial 0\2

  2. what router model did you use? I cannot use the command "Distrib-list"