Sprint/HiNet

Thu Aug 27 03:07:08 UTC 1998

On Wed, 26 Aug 1998, Phil Howard wrote:

> william at pacific.net.ph writes:
> 
> >   8     *        *        *     Request timed out.
> > 
> > Line 8 is always like this and a customer of ours is complaining about it.
> > Is this a time out or congestion or something else?
> 
> Most likely there is a private address (in one of 10.0.0.0/8, 172.16.0.0/12,
> or 192.168.0.0/16) being used there.  Tell the customer it is not their
> router and to not worry about it.
> 
> Private addresses are often used this way.  There are complications to it,
> and this is one of those.

Unless someone upstream from your location is blocking packets sourced
from private space, that's probably not what's happening here.  Remember
at no time during a traceroute are you sending packets directly to any hop
along the way, all packets have the destination address of the address
you're tracing to.  On the way back they have a source address of the
router along the way, which might be private, but have a destination
address of the machine you started the traceroute from.

More likely the router in question is just not sending ICMP TTL expired,
or it is unable to route packets going back toward you for some reason.
As others have said, tell the customer that as long as the packets make it
_through_ the router, it's not a problem.

Brandon Ross            Network Engineering     404-815-0770 800-719-4664
Director, Network Engineering, MindSpring Ent., Inc.  info at mindspring.com
                                                            ICQ:  2269442

Stop Smurf attacks!  Configure your router interfaces to block directed
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