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Re: [LUG] Oddity...

 

stinga wrote:

> Might be a load of rubbish, but...

It is :)

> traceroute uses ping, it might be that the 6th hop host is not  
> responding to ping, I have seen this and assumed this was the issue.

Traceroute does not use ping.

ping sends an ICMP echo request packet to the target system, which
responds with the echo reply assuming it isn't firewalled or disabled
some other way.

traceroute sends packets with increasing TTLs creating a "map" of the
path between the source and target by finding the host that bounces
the packet with a TTL exceeded error.  AFAIR, the packets it sends are
udp packets addressed to random high-numbered ports.

There are all sorts of reasons traceroute may be unable to complete a
route to the target, including intervening firewalls, systems configured
to block TTL exceeded responses and all sorts of bizarre routing
arrangements.

James

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