nanog mailing list archives

Re: Cool IPv6 Stuff


From: Adrian Chadd <adrian () creative net au>
Date: Tue, 5 Jun 2007 10:29:43 +0800


On Mon, Jun 04, 2007, Iljitsch van Beijnum wrote:

On 4-jun-2007, at 17:37, Donald Stahl wrote:

I want NAT to die but I think it won't.

Far too many "security" folks are dictating actual implementation  
details and that's fundamentally wrong.

A security policy should read "no external access to the network"  
and it should be up to the network/firewall folks to determine how  
best to make that happen. Unfortunately many security policies go  
so far as to explicitly require NAT.

Don't forget that the reason NAT works to the degree that it does  
today is because of all the workarounds in applications or protocol- 
specific workarounds in the NATs (ALGs). In IPv6, you don't have any  
of this stuff, so IPv6 NAT gets you nowhere fast with any protocol  
that does more than something HTTP-like. (Yes, I've tried it.)

Won't stateful firewalls have similar issues? Ie, if you craft a stateful
firewall to allow an office to have real IPv6 addresses but not to allow
arbitrary connections in/out (ie, the "stateful" bit), won't said stateful
require protocol tracking modules with similar (but not -as-) complexity
to the existing NAT modules?




Adrian


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