[dns-operations] First experiments with DNS dampening to fight amplification attacks

WBrown at e1b.org WBrown at e1b.org
Fri Oct 26 15:15:35 UTC 2012

paul vixie <paul at redbarn.org> wrote on 10/26/2012 10:32:57 AM:

> i just don't see it. there isn't more to it than that. from the point of
> view of everyone on the connected internet, it is a bad idea to let some
> new person connect some new router that forwards packets, if that person
> is unaware of the s.a.v. issue. if a vendor won't make s.a.v. the
> default because they need the new business and they don't want the
> training burden of making sure they understand the issues of s.a.v.,
> then they are following the 'chemical polluter business model' where the
> money is made "here" and the impact is only felt "over there".

I'm not an internet routing guru, so I must not be seeing something.  When 
my organization connects to an upstream provider, they know we have a 
block of addresses assigned (Actually, we have more than one).  They know 
that we connect to their switch in rack X, switch Y, port Z.

If they see a packet with a source address of appearing on that 
port, what possible reason could they have for allowing it through? 

Obviously, that's a Google address, and possibly forged a lot.  I just 
don't see why a packet claiming to be from an address we do not own should 
be coming from our net.  Can anyone explain why that would happen (other 
than forgery)?

I looked at BCP84/RFC3704, but as a non-networking person, it was brushing 
the bald-spot. 

I know this is drifting from the list topic, so thank you for the 

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