traceroute is not working but pinging

nilesh.dubey · ‎02-08-2016

I can ping an IP address but not traceroute. When I am trying to traceroute getting below response. Could anyone assist me to resolve it.

1 * * *
2 * * *
3 * * *
4 * * *
5 * * *
6 * * *
7 * * *
8 * * *
9 * * *
10 * * *
11 * * *
12 * * *

Regards

Nilesh

Jon Marshall · ‎02-08-2016

Difficult to say without knowing what devices are between the source and destination IP.

Ping simply sends an ICMP packet to the destination IP and gets a response back.

Traceroute on the other hand sends ICMP packets with increasing TTLs so each L3 device along the path has to send a response to source IP.

So it could be acls, firewalls, router configurations etc. that are stopping the traceroute from working correctly.

Jon

milan.kulik · ‎02-09-2016

Hi,

Cisco is using UDP for traceroute actually.

So if the source device would be a Cisco switch, e.g., there could be an ACL or FW rule permitting ICMP echo (=Ping) but denying UDP (=traceroute) causing the symptoms?

Best regards,

Milan

nilesh.dubey · ‎02-10-2016

Hi Jon,

There is no such access-list on router but I am not sure about the firewall, if it would be blocking.

Regards

Nilesh

paul driver · ‎02-08-2016

Hello

Following on from Jons response- On the router try and either disable IP domain-lookup or use the numeric command

By default traceroute performs dns resolution

traceroute xxxxxx numeric

Res

Paul

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Paul

nilesh.dubey · ‎02-10-2016

Hi Paul,

I tried that but it did not work.

Regards

Nilesh

CSCO12302959 · ‎07-13-2018

Even if ICPM can be inspected and you can ping to the internet but when you do a trace to the same IP as you ping the firewall will block the returning traffic, I had the same problem until I allow icmp from any to the internal IPs as traffic hit the outside interface then everything worked.