Revealed: The Internet's well known BGP behavior

John Lee john at
Wed Aug 27 22:47:53 CDT 2008


The traceroute utility that I used gave me a list of hops that the packet I was interested in transited and a time when it transited the hop. When the TTL was reached it would terminate the listing.

When ever I had performance issues on my networks or with my networks links it would indicate if the standard route was being taken or another one. When certain links went down several additional hops would be added to the list.

John (ISDN) Lee

From: Adrian Chadd [adrian at]
Sent: Wednesday, August 27, 2008 11:32 PM
To: John Lee
Cc: Patrick W. Gilmore; NANOG list
Subject: Re: Revealed: The Internet's well known BGP behavior

On Wed, Aug 27, 2008, John Lee wrote:
> Patrick,
> VPN's and MPLS control intermediate hops and IPsec and SSL do not allow the info to be seen.
> Rewriting the TTL only hides the number of hop count, trace route will still show the hops the packet has transited.

No, traceroute shows the hops which returned "time to live exceeded."

This only maps to "the hops the packet has transited" if the TTL is setup
and decremented correctly.


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