Traceroute losses through

Jared Mauch jared at
Fri Sep 16 18:50:28 UTC 2011

On Sep 16, 2011, at 2:42 PM, Steve Bohrer wrote:

> My general question is "what meaning do I give to lossy traceroutes, even when pings show no problem."
> Can I expect that backbone routers should never give me timeouts on a traceroute through them, so, lots of asterisks from these systems indicate a packet loss problem that needs to be fixed?
> Or, are these traceroute asterisks essentially meaningless, and should be expected on any busy link?

Basically, you should expect timeouts in the middle of the path from any large network from time-to-time.

It could be for any number of reasons, ddos, control-plane "busyness", etc..

There was even a provider that once limited the ability for people to see inside their network.

The true tests are always end-to-end tests.  I recommend having a host at each end that you can run pings or iperf from.  This will aide you greatly in diagnosing the trouble.  Traceroute (or, more specifically TTL expiry handling by a multipurpose device) is often lower on the priority list than things to keep the element "alive and operational".

Your outputs showed good results on each end of the path, meaning that the device was perhaps rate-limiting the TTL expiry traffic or had something else going on.

- Jared

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