Distribution-list

for this lab, we gonna use same topology and setup from previous lab Redistribution RIP Ver2 - OSPF

1. First we gonna stop route to 172.16.2.x and 172.16.3.x to be advertised into R2

on R1 create access-list to match the two address

ip access-list standard ROUTE_FILTER
 deny   172.16.3.0 0.0.0.255
 deny   172.16.4.0 0.0.0.255
 permit any //don't forget this, by default access-list deny all

then apply inside the routing protocol on specific interface, in this case, go to RIP and apply on the R1 interface serial 0/0

router rip
 version 2
 network 10.0.0.0
 network 172.16.0.0
 distribute-list ROUTE_FILTER out Serial0/0
 no auto-summary

now check on R2, R3 and R4, you should see no route to this two network


2. Now we gonna apply distribution list where the filter is applied between routing protocol, here we gonna filter network 172.16.1.x coming from RIP from being advertised into OSPF

 on R2, create access-list for this network


ip access-list standard ROUTE_FILTER
 deny   172.16.1.0 0.0.0.255
 permit any

because OSPF don't want specific network to advertise to him, we gonna configure this inside the OSPF process and specific from what routing protocol and network he don't want any update

router ospf 1

 router-id 2.2.2.2

 log-adjacency-changes

 redistribute rip subnets

 network 10.0.0.0 0.255.255.255 area 0

 distribute-list ROUTE_FILTER2 out rip

check on the R3, R4. there should be no route path to 172.16.1.x