Re: [midcom] Port preservation

Jonathan Rosenberg <jdrosen@dynamicsoft.com> Tue, 27 April 2004 16:28 UTC

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Date: Tue, 27 Apr 2004 11:48:31 -0400
From: Jonathan Rosenberg <jdrosen@dynamicsoft.com>
Organization: dynamicsoft
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CC: 'Cullen Jennings' <fluffy@cisco.com>, 'Yutaka Takeda' <takeday@pcrla.com>, 'Midcom' <midcom@ietf.org>, stun@www.vovida.org
Subject: Re: [midcom] Port preservation
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I think you are confusing two things.

One is a client behind a nat speaking to a server on the public side. 
There, I think there are very, very few cases where the source port 
means anything (IKE is the only identified one there).

The other case is a server running behind the NAT (i.e., on the private 
side), which is what you are talking about below. In such a case, I 
think you would use port forwarding configuration on the nat, and so 
port preservation on dynamically created bindings isnt applicable.

-Jonathan R.

Christopher A. Martin wrote:

> I guess I should also state the port that I am describing is a listening
> port (which is often also the source port) of the server being NATted,
> while I am at it.
> 
> -----Original Message-----
> From: midcom-admin@ietf.org [mailto:midcom-admin@ietf.org] On Behalf Of
> Christopher A. Martin
> Sent: Tuesday, April 27, 2004 8:09 AM
> To: 'Cullen Jennings'; 'Jonathan Rosenberg'
> Cc: 'Yutaka Takeda'; 'Midcom'; stun@www.vovida.org
> Subject: RE: [midcom] Port preservation
> 
> Ya, clients typically do use random ports, I am only speaking from a
> server standpoint (Enterprises don't typically static nat a client).
> 
> :)
> 
> Chris
> 
> -----Original Message-----
> From: Cullen Jennings [mailto:fluffy@cisco.com] 
> Sent: Tuesday, April 27, 2004 12:37 AM
> To: Chris@sip1.com; Jonathan Rosenberg
> Cc: 'Yutaka Takeda'; Midcom; stun@www.vovida.org
> Subject: Re: [midcom] Port preservation
> 
> On 4/26/04 7:00 PM, "Christopher A. Martin" <chris@sip1.com> wrote:
> 
> 
>>For clarity, common server ports in this example would be HTTP, SMTP,
>>FTP, etc.
> 
> 
> Well for TCP, the NATs don't muck with ports at all. The clients I have
> for
> HTTP, SMTP, FTP, also use source ports different than the destination
> ports
> so that the clients don't have to open a port under 1024 which would
> require
> them to be running as root.
> 
>  
> 
> 
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> midcom@ietf.org
> https://www1.ietf.org/mailman/listinfo/midcom
> 

-- 
Jonathan D. Rosenberg, Ph.D.                600 Lanidex Plaza
Chief Technology Officer                    Parsippany, NJ 07054-2711
dynamicsoft
jdrosen@dynamicsoft.com                     FAX:   (973) 952-5050
http://www.jdrosen.net                      PHONE: (973) 952-5000
http://www.dynamicsoft.com

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