From: Malcolm Price (malcolm.price@lanbase.com)
Date: Tue Mar 27 2007 - 17:47:01 ART
Hi group,
Has anyone ever seen a case whereby you have two catalysts (3560 L3) running
eigrp on the same LAN. Cat A and Cat B form adjacencies and exchange
hello's. However when cat B receives cat A's routes all the routes learned
from A are stamped as destination unreachable.
I've put a sniffer trace on router B and inspected the eigrp update packets
entering router B.
The source IP of the packet entering CAT B is 10.1.1.1 (cat A) and the
destination IP address is the multicast address, 224.0.0.10. However, I
would expect this destination address to be 10.1.1.2 (Cat B) ?.
In the IP EIGRP UPDATE packet entering router B the details are:
IP Internal Route = 10.2.0.0/16 - Destination unreachable
Type = 0x0102 (IP Internal Route)
Size 27 bytes
Next Hop = 0.0.0.0
Metrics etc
Prefix = 16
Destination = 10.2.0.0
The route 10.2.0.0/16 is being advertised by Catalyst A. This is a valid
subnet local to Cat A.
The eigrp configuration itself is pretty simple,
Router eigrp 254
Network 10.0.0.0
No auto-summary
I could understand the next hop set to 0.0.0.0 if this was being advertised
OUT by Cat B as this would be self/the origin but this is a packet being
Received into Cat B which doesn't add up.
Does anyone have a description of the EIGRP packet format and perhaps an
explanation why the route is flagged as unreachable.
Many thanks in advance,
Malcolm
This archive was generated by hypermail 2.1.4 : Sun Apr 01 2007 - 06:35:53 ART