Solution:- EIGRP is one of the most popular Cisco proprietary Routing Protocols due to its features like Rapid convergence, Support for IP, IPX, Appletalk. We know that It is very easy to run but sometimes small mistakes or ignorance make it very tough to resolve problems.
Here are some of the important points one can follow
- Verify the physical connectivity between these two Routers. Make sure the cable or link is connected to the correct or designated interfaces
- Verify that the IP address assignment along with subnet mask is correct on both routers. Both IP addresses should be part of same network Domain. Interfaces should be in UP state.
- Verify whether you can ping each other from both ends or if ping is not supported or blocked, then verify ARP entries.
- Verify “Show ip protocol” to check if eigrp is running or not. Both routers should have same Autonomous System configured
- Verify the K values, it should be set as same on both ends
- Verify that there is no restriction( access-list or Firewall blockage) of EIGRP traffic which may cause neighborship problems.
- Verify that the common subnet of R3 and R4 is advertised in eigrp on both routers.
- Verify that Authentication parameters are matching in eigrp configuration at both ends, if authentication is being used.
- Also verify that CPU and Memory resources are not over utilized on both routers.
- Make sure that Passive Interface statement does not exist for the interfaces which are being used for EIGRP.