Single IP address routing differently. Possible?

[shaun-murray]

We have a 3560, that when you ping the 10.80.0.0 network (switch being on the 10.90.0.0 network), it can ping EVERYTHING on that subnet fine. Except for one IP address. Which is being routed a different way, then being caught in a loop between two devices. What could cause this? Please let me know what info you need from my end if need be! Thanks!!!! -Shaun

[rais]

You should do a route lookup on that particular host and see if the next differ for the route lookup for 10.80.0.0 network.

Thanks.

[Richard Burts]

Shaun

The symptoms you describe sound like some device has a static route for that host (or perhaps an incorrect ARP entry). To troubleshoot this issue I would ask you to post the output of a traceroute for some address that does work and the output of a traceroute to the address that does not work. The first hop(s) should be the same. At some point the hops will be different. The last device before they become different is probably the device with the extra/incorrect entry. On that device do show ip route and look to see if there is an entry that matches the particular address. Perhaps you can post the output of show ip route so we can see.

HTH

Rick

[shaun-murray]

clear ip arp interface vlan1

Now it works like a champ! Why would something like that happen? Just build up over time, and bad routes being snuck in? Anyways. Thanks for the direction guys!

Also... "route lookup" This is a switch, unless I'm missing something... *shrug*