Conditional default advertisement based on two routes


RIP can be configure to advertise a default route on the basis of two routes being present in the routing table. If either of these routes isn’t in the table the default is withdrawn.

Configuration

1) Create tracks to track the existence of the 2 routes in the routing table.

R4(config)#track 1 ip route 5.5.5.5/32 reachability R4(config)#track 2 ip route 1.1.1.1/32 reachability

2) Create a boolean track to tie the 2 tracks together. Here I’m using “and” but can use “or” and “not” on the objects in the list.

R4(config)#track 3 list boolean and R4(config-track)#object 1 R4(config-track)#object 2 R4(config-track)# *Mar  1 00:38:55.867: %TRACKING-5-STATE: 3 list boolean and Down->Up

3) Create a static route with the track tied to it. This route is to null0 and doesn’t provide any reachability, it just allow for us to match it later on.

R4(config)#ip route 100.100.100.100 255.255.255.255 null0 track 3

4) Create a prefix-list to match the route above

R4(config)#ip prefix-list Track3 permit 100.100.100.100/32

5) Create a route-map that matches the null0 route using the prefix list

R4(config)#route-map Default-ADV permit 10 R4(config-route-map)#match ip add prefix-list  Track3

6) Use the Route-map in the default-information originate under the RIP process

R4(config)#router rip R4(config-router)#default-information originate route-map Default-ADV

Now a default route should be visible to the other routers

Note: by using set interface in the route-map you can control the interface(s) the default will be sent from.

Advertisements

About ccie4all
Hello, and welcome to the first post of my CCIE blog This blog has got one simple goal and that is to improve our skills in Cisco Networking field so we can become best engineers on a job market. Wordpress Blog https://ccie4all.wordpress.com/ information about the changes made to Gns3 BGP , MPLS and R&S CCIE labs. In order to access and download all provided materials and receive important updates from Gns3 BGP , MPLS and R&S CCIE labs under GNS3 tab in the main header please go ahead and subscribe to https://ccie4all.wordpress.com/ ! All other posts have not been affected and can be accessed at any given time. Enjoy ! Tom

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: