[IPTABLES] Symmetric NAT?

Olivier GRALL olivier.grall at neotip.com
Fri Oct 14 14:10:46 CEST 2005


Hi,

I was making some tests with STUN when I realize that my NAT box was a 
simple Linux Box with an IPTABLES rule with a MASQ target. What seemed 
strange to me was that the STUN result was "Port restricted cone ".

I made a new with NATcheck.exe... same result.
http://midcom-p2p.sourceforge.net/

I was sure IPTABLES NAT was Symmetric and not Port restricted cone. What 
about it ?
In the "Procceding of NetFilter Developer WorkShop 2004",  Harald Welte 
reported "

netfilter however implements (SNAT and MASQ) as ssymmetric.
"


For me, with MASQ it is Port restricted cone and with SNAT+DNAT it is 
Symmetric. Is it true ?

Thanx,

-- 

	
Olivier GRALL
R&D Engineer 	*NeoTIP** S.A.*
4, rue Louis de Broglie
22300 Lannion
France
olivier.grall at neotip.com <mailto:olivier.grall at neotip.com> 	+33 (0)2 96 
48 66 94




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