Re[2]: SYN floods (was: does history repeat itself?)

[pcalhoun () usr com (Pat Calhoun)]

     Perry,
     
        This is actually quite simple to implement on Dial Access Routers, 
     and obviously this is the best place to add the filtering. 
     
     
     Pat R. Calhoun                                e-mail: pcalhoun () usr com 
     Project Engineer - Lan Access R&D                phone: (847) 933-5181 
     US Robotics Access Corp.


______________________________ Reply Separator _________________________________
Subject: Re: SYN floods (was: does history repeat itself?) 
Author:  "Perry E. Metzger" <perry () piermont com> at Internet
Date:    9/9/96 1:19 PM


     
Re: SYN floods
     
PANIX, a large public access provider in New York, was badly hit with 
SYN flood attacks from random source addresses over the last few 
days. It nearly wrecked them.
     
I think its time for the larger providers to start filtering packets 
coming from customers so that they only accept packets with the 
customer's network number on it. 
     
Yes, its a load on routers. Yes, its nasty for the mobile IP weenies. 
Unfortunately, the only known way to stop this. Many TCPs go belly up 
as soon as they get SYN flooded -- its a defect in the protocol 
design, and other than Karn style anti-clogging tokens ("cookies") 
being put into a TCP++ and mass implemented worldwide soon, the only 
reasonable way to stop this sort of terrorism is provider filtering.
     
Perry

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