Content

| 5.6 |  | Troubleshooting EIGRP |
| 5.6.7 |  | EIGRP error messages |

This section discusses some of the most common EIGRP errors that appear and the meaning behind these EIGRP error messages.

DUAL-3-SIA
This message means that the primary route is gone and no feasible successor is available. The router has sent out the queries to its neighbor and has not heard the reply from a particular neighbor for more than three minutes. The route state is now stuck in active state.

Neighbor is not on common subnet
This message means that the router has heard a hello packet from a neighbor that is not on the same subnet as the router.

DUAL-3-BADCOUNT
Badcount means that EIGRP believes that it knows of more routes for a given network than actually exists. It is typically, but not always, seen in conjunction with DUAL-3-SIAs, but it is not believed to cause any problems itself.

Unequal, <route>, dndb=<metric>, query=<metric>
This message indicates that there is an EIGRP internal error. However, the router is coded to fully recover from this internal error. The EIGRP internal error is caused by a software problem and should not affect the operation of the router. The plan of action is to report this error to the Cisco TAC and have the experts decode the traceback message. At some point the Cisco IOS Software should be upgraded accordingly.

IP-EIGRP: Callback: callback_routes
At some point, EIGRP attempted to install routes to the destinations and failed, most commonly because of the existence of a route with a better administrative distance. When this occurs, EIGRP registers its route as a backup route. When the better route disappears from the routing table, EIGRP is called back through callback_routes so that it can attempt to reinstall the routes that it is holding in the topology table.

Error: EIGRP: DDB not configured on interface
This means that when the routers interface receives an EIGRP hello packet and the router attempts to associate the packet with a DUAL descriptor block (DDB) for that interface, it does not find one that matches. This means that the router is receiving a hello packet on the interface that does not have EIGRP configured.

Poison squashed
The router threads a topology table entry as poison in reply to an update (the router set up for poison reverse). While the router is building the packet that contains the poison reverse, the router realizes that it does not need to send it. For example, if the router receives a query for that route from the neighbor, it is currently threaded to poison.