Consumer networking head scratcher

Ryan Pugatch rpug at
Wed Mar 1 19:31:20 UTC 2017

On Wed, Mar 1, 2017, at 02:04 PM, William Herrin wrote:
> > On Wed, Mar 1, 2017, at 01:23 PM, Aaron Gould wrote:
> >> That's strange... it's like the TTL on all Windows IP packets are
> >> decrementing more and more as time goes on causing you to get less and
> >> less hops into the internet
> Hi Ryan,
> Windows tracert uses ICMP echo-request packets to trace the path. It
> expects either an ICMP destination unreachable message or an ICMP echo
> response message to come back. The final hop in the trace will return
> an ICMP echo-response or an unreachable-prohibited. The ones prior to
> the final hop will return an unreachable-time-exceeded if they return
> anything at all.
> If the destination does not respond to ping, if those pings are
> dropped, or if it responds with an unreachable that's dropped you will
> not receive a response and the tracert will not find its end. That's
> why you're seeing the "decrementing" behavior you describe.
> I have no information about whether comcast blocks pings to its routers.
> Regards,
> Bill Herrin

I see what you're saying, and that could explain the decrementing
behavior I'm seeing which ultimately is not a real indicator of the
problem I am having.

So in that case, I would be back to my original issue where I stop being
able to pass traffic to the Internet, and when that happens my
traceroute always dies at the same hop.  After disconnecting and
reconnecting, the same traceroute will go all the way through.

Thanks for the thoughts.

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