The figure shows a flowchart for diagnosing EIGRP connectivity issues.

After configuring EIGRP, the first step is to test connectivity to the remote network. If the ping fails, confirm the EIGRP neighbor adjacencies. Neighbor adjacency might not be formed for a number of reasons, including the following:

Aside from these issues, there are a number of other, more advanced issues that can cause neighbor adjacencies to not be formed. Two examples are misconfigured EIGRP authentication or mismatched K values, which EIGRP uses to calculate its metric.

If the EIGRP neighbor adjacency is formed between the two routers, but there is still a connection issue, there may be a routing problem. Some issues that may cause a connectivity problem for EIGRP include:

If all of the required routes are in the routing table, but the path that traffic takes is not correct, verify the interface bandwidth values.