Cisco router dropping icmp echo requests

[tinklas9001]

Hi,

I would like somebody to explain is this common behavior of Cisco catalyst routers to drop pings to them. We have a Cisco router and when using WinMTR or Windows tracert program we observe some packet loss at our Cisco router (10-50%), but there seems to be no loss at further hops however. Is this nothing to worry about and it has no influence on network performance or this can be the reason why we experience some lags in foreign traffic?

[Mark Malone]

You shouldn't be dropping packets , are you directly connected to the router testing this or coming through another device ?

Have you tested from different pcs/laptops is it the result the same to result to rule out the local nic ?

Can you post the show interface of the router your directly connected too , have you replaced the cable in case somethings loose

[tinklas9001]

Well, the thing is that the only packets dropped are the ones meant for the router itself. That is, if we ping some website on the Internet - there is no loss in that case.

[Mark Malone]

How are you testing this ? if I ping any loopback on my devices they don't drop any packets or any of there interfaces

If your dropping 10-50% of traffic there could be an issue , is the router under stress cpu / memory etc  , not unless the cp is dropping it somehow

[tinklas9001]

I use WinMTR or Windows tracert command and input some distant website like cnn.com. There is no loss shown on further nodes, but only on our router hop.

[Mark Malone]

Ok do you see the same results if you run an actual ping to the website ip address at same time  ?

when you say loss on router ip does it actually stop * * * or does it just show latency increase ? do your pings fail with .......

[Iulian Vaideanu]

A common practice is to protect routers from unwanted traffic that targets the router itself (like floods / DoS for example) by configuring some form of CoPP (control plane policing) - after all, a router's job is to move traffic from one interface to another, not to answer pings :)...