Subject: [midcom] NAT types of commercial routers

From: [email-masked]
Date: Tue, 26 Aug 2003 13:08:55 -0400

Hi all,

The STUN RFC describes several types of NATs based on their behaviors on UDP traffic. Does anyone have a list of what commercial routers belong to which types? If don't, can we start a list somewhere by reporting what we know? I have tested a couple Netgear routers and they are full cone. We tested a Linksys NR041 during SIPit13 and it appeared to be Symmetric. Any one know of any restricted or port restricted NAT out there?

Thanks a lot!

BR

Tat Chan
Senior Research Engineer
Nokia Research Center
NOKIA INC
5 Wayside Road, Burlington, MA 01803
Phone (781) 993-5776, Fax (781) 993-1907
[email-masked]

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From: Bryan Ford <[email-masked]>
Date: Wed, 27 Aug 2003 12:40:13 -0400

On Tuesday 26 August 2003 01:08 pm, [email-masked] wrote:
> Hi all,
>
> The STUN RFC describes several types of NATs based on their behaviors on
> UDP traffic. Does anyone have a list of what commercial routers belong to
> which types? If don't, can we start a list somewhere by reporting what we
> know? I have tested a couple Netgear routers and they are full cone. We
> tested a Linksys NR041 during SIPit13 and it appeared to be Symmetric. Any
> one know of any restricted or port restricted NAT out there?

That's exactly the type of information I'm trying to gather at my "NAT Check" 
page:

	http://pdos.lcs.mit.edu/~baford/nat/

...although the program and the results submission form/results table 
currently don't use the exact terms "cone NAT", "symmetric NAT", etc.  Also, 
NAT Check as it currently is might not collect all the information you could 
possibly want (e.g., it currently doesn't try to distinguish between 
"restricted cone NATs" and "port-restricted cone NATs", though it does 
distinguish between full cone NATs and [port] restricted cone NATs).  I'd 
always welcome enhancements to NAT Check to make it gather more information 
or whatever.

Cheers,
Bryan