Friday, March 25, 2011

Lab 65 - RIPv2 Conditional Default Routing Advertisement

Prerequisites: CCNP level skills.

Topology
Pic. 1 - Topology Diagram.
Icons designed by: Andrzej Szoblik - http://www.newo.pl

Task1
Configure R3 to advertise a default to its RIP neighbors. In case R3's F1/0 interface is down it should stop advertising the default route. (this option does not work if R5's F1/0 interface is down or is inaccessible for some other reason). Do not advertise the default route towards R5.

Lab Solution

Task1
Configure R3 to advertise a default to its RIP neighbors. In case R3's F1/0 interface is down it should stop advertising the default route (this option does not work if R5's F1/0 interface is down or is inaccessible for some other reason). Do not advertise the default route towards R5.

R3 Configuration:
!
ip access-list standard LINK_TO_R5
 permit 10.1.35.0 0.0.0.255
!
route-map CHECK_LINK permit 10
 match ip address LINK_TO_R5
 set interface Serial0/1 Serial0/2
!
router rip
 version 2
 passive-interface Loopback0
 network 10.0.0.0
 network 172.16.0.0
 default-information originate route-map CHECK_LINK
 no auto-summary
!

Verification:
Pic. 2 - R1's Routing Table.

Pic. 3 - R5's Routing Table.
Notice!
This method will make R3 to stop advertising the default route only in case the link between R3 and R5 is down.

Shutting down int F1/0 triggers the flash update: 0.0.0.0/0 is poisoned.

Pic. 4 - Flash Update.