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Re: How NAT reacts on table flood ?
From: Lynx <lynx () enemy org>
Date: Tue, 11 Jul 2006 18:57:04 +0200

On Jul 11, 2006 at 1515 +0200, Norbert François appeared and said:

I was wondering how the NAT reacts when its translation table is
full... For example, suppose that you've 100 computers behind a NAT
(University) and one (or more) of them engages purposely  a lot of
connexion, in order to fill the NAT table, what will occur ?

That depends on your NAT implementation. I know from firsthand scanning
experience that a Linux router with stateful NAT tracking (i.e.
Netfilter-based) can be flooded (tested on 2.4.x and 2.6.x). After the
NAT table is filled the kernel has to wait for the state table entries
to timeout. There is an alternative way of doing NAT via the Linux
routing code. Unfortunately I don't know how this method performs.


FAITH, n. - Belief without evidence in what is told by one who speaks
            without knowledge, of things without parallel.
 -- http://www.alcyone.com/max/lit/devils/f.html --

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