Using distance as a filter in EIGRP


Distance command can be used as a filter by setting the administrative distance (AD) of a route above another so it will take over (the other route will be there ready to take over if the other is lost) or filtering it completely by using an AD of 255

R1 is receiving some routes from R2 and R3 on the same interface f0/0

R1(config-if)#do sh ip ro ei
1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
D       1.0.0.0/22 is a summary, 00:34:30, Null0
D    2.0.0.0/8 [90/409600] via 10.1.1.2, 00:18:21, FastEthernet0/0
3.0.0.0/24 is subnetted, 1 subnets
D 3.3.3.0 [90/409600] via 10.1.1.3, 00:00:09, FastEthernet0/0

In this configuration we are going to filter out 3.3.3.0/24 from R1′s routing table using distance command.

Configuration

1) configure and ACL to match the routes to be removed.

R1(config)#access-list 3 permit host 3.3.3.0

2) Under the EIGRP routing process configure the distance command to filter the route in ACL 3 from R3 (10.1.1.3)

R1(config)#router ei 100

R1(config-router)#distance 255 10.1.1.3 0.0.0.0 3

We can see the route is now gone from the routing table.

R1(config-router)#do sh ip ro ei
1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
D       1.0.0.0/22 is a summary, 00:37:21, Null0
D    2.0.0.0/8 [90/409600] via 10.1.1.2, 00:00:08, FastEthernet0/0

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: