Hi, I have a pair of routers running OpenBSD 4.2 release, each with four ethernet interfaces (fxp0, fxp1, fxp2, fxp3) and carp on all four interfaces. fxp0 and fxp1 are /30 networks over which I run BGP sessions to our upstream providers.
Router A is the primary machine with advskew 0 and Router B is the backup machine with advskew 50. When I unplug an ethernet connection on Router A to simulate a failure, all of the carp interfaces become MASTER and the BGP sessions are re-established, as expected. However, I am experiencing some strange behaviour. When the backup router is active, traffic destined for the Internet (through the BGP peers) doesn't reach it's destination and ICMP TTL expired messages are received back from Router B. Looking at the routing table, the following line appears on Router B when it becomes carp MASTER: Destination Gateway Flags Refs Use Mtu Interface 80.x.y.154 00:00:5e:00:01:01 UHLc 1 2 - lo0 This entry does not appear on Router A when it is in operation (and routing traffic correctly). Could this interesting-looking router be something associated with the routing loop I'm seeing? I appreciate that I may not have provided enough information for a correct diagnosis of the problem. I will be happy to provide more details on request. Many Thanks, Charlie
