• BGP v1.1

  
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When we type “network 10.0.0.0”, the EIGRP process looks at 10.0.0.0 network and turns on EIGRP on all the interfaces whose IP Address is in the subnet 10.0.0.0. Then EIGRP advertise the network which is the IP Address of the interface. For example, when I mentioned the below IP address on an interface

EIGRP process advertised 172.16.0.0/24 which was under the interface as shown below:

 

 

 

When a router advertises a default route to another router, it thinks that it has route to all the networks, that’s why it’s summarizing all the routes as one default route. Considering this, there is no need for the default route installed on it since it already has an individual route to every network (according to router thinking). So, it installs a route with a default route directing to NULL interface.

Cause Analysis

Routing table of Corp Router showed RIP entry instead of EIGRP.

Network Diagram

Handaling Process &  Solution

For resolving this problem I undertook the following steps:

 

1)    After applying redistribution on R3, I checked that the router 871W and hostd were able to see all the routes on the other side of R3 as RIP routes.     That was normal.

2)    Then I checked Corp Router and found out that Corp showed the route 10.1.12.0 as a RIP Entry. Corp Router was basically running both RIP and EIGRP. Static routes were also installed in Corp with AD of 150.

3)     I stopped RIP on Corp, and checked again. This time a static route took the place of RIP Entry for 10.1.12.0 network.

      4)   I checked the topology table of EIGRP and found the following error:

 

 

The route to 10.1.12.0 showed “FD is Inaccessible” which meant that the EIGRP route in the topology table for the network 10.1.12.0 was not being used for the routing table.

      5) After that I removed static entry as well. EIGRP route was successfully added to the routing table with AD of 170 as shown below

 

         

     6) The route from redistribution is considered as an external route in EIGRP. That’s why we saw RIP and static route in the routing table instead of   

          EIGRP.