Got a very strange routing problem. Had a fault come in that a voice server was inreachable (10.102.6.2). A traceroute seemed to see 10.102.254.17 as the second hop and all subsequent hops as well! This address is the exit interface of a 3845 router (first hop was the WAN address of this router). 10.102.0.0/16 is forwarded to a firewall on the directly connected subnet 10.102.254.0/28.
Funny thing is that trace to the IP address 10.102.6.3 routes ok and tracing to 10.102.6.2 on the 3845 gives it's own ip address as the first hop!
Very odd and am currently suspecting an IOS fault. Change control is a nightmare so am exhausting all other options first.
3845#sh ip arp | in 10.102.254.18
Internet 10.102.254.18 203 0023.336b.0000 ARPA GigabitEthernet0/1.16
3845#sh ip route 10.102.6.2
Routing entry for 10.102.0.0/16
Known via "static", distance 1, metric 0
Redistributing via eigrp 110
Advertised by eigrp 110
Routing Descriptor Blocks:
Route metric is 0, traffic share count is 1
Type escape sequence to abort.
Tracing the route to 10.102.6.2
1 10.102.254.17 0 msec 0 msec 4 msec
2 * * *
3 * * *