Re: 3500 traceroute's fail

candv · ‎09-03-2003

Dear All, I am tracerouting between a few 3500's, they running 12.05(WC2) and am experiencing weird results(All in same subnet no acl's). I can traceroute from one 3500 to another and do a debug on icmp and ip packets and can see the packets get through to the destination but I do not see a port unreachable reply, below is a good result (no 2nd probe result though just a * everytime)

Sep 3 12:08:01: IP: s=137.4.233.69 (VLAN999), d=137.4.233.60, len 28, rcvd 1

Sep 3 12:08:01: ICMP: dst (137.4.233.60) port unreachable sent to 137.4.233.69

Sep 3 12:08:01: IP: s=137.4.233.60 (local), d=137.4.233.69 (VLAN999), len 56, sen

ding

Sep 3 12:08:01: IP: s=137.4.233.69 (VLAN999), d=137.4.233.60, len 28, rcvd 1

Sep 3 12:08:04: IP: s=137.4.233.69 (VLAN999), d=137.4.233.60, len 28, rcvd 1

Sep 3 12:08:04: ICMP: dst (137.4.233.60) port unreachable sent to 137.4.233.69

Sep 3 12:08:04: IP: s=137.4.233.60 (local), d=137.4.233.69 (VLAN999), len 56, sen

ding

But if I traceroute to another switch I get

Sep 3 12:09:32: IP: s=137.4.233.69 (VLAN999), d=137.4.233.61, len 28, rcvd 1

Sep 3 12:09:35: IP: s=137.4.233.69 (VLAN999), d=137.4.233.61, len 28, rcvd 1

Sep 3 12:09:38: IP: s=137.4.233.69 (VLAN999), d=137.4.233.61, len 28, rcvd 1

and do not see any port unreachables. I have upgraded the software to 12.05(wc8) and again same things happen.

When I do a show ip traffic there is no data in the icmp unreachable column

ICMP statistics:

Sent: 0 redirects, 0 unreachable

anyone seen anything like this?

DWAM_2 · ‎09-03-2003

Hello,

Could you past 2 configurations of 2 unreacheable switchs?

I think you have realised that but :

-> check cable and led on (layer 1)

-> check cdp if activated (cdp neighbours particulary) (layer 2)

-> check vlan up (layer 3 using ping )

-> check telnet if activated (layer 7 ok)

Regards