Subject: RE: [Ietf-behave] port-type preservation?

From: "Francois Audet" <[email-masked]>
Date: Wed, 29 Sep 2004 15:51:16 -0700 (PDT)

So, if I understand correctly, you want us to put in the Behave document
something saying that port binding assignments are to be done from the 
dynamic/private port range 49152-65535?

Right?

> -----Original Message-----
> From: ietf-behave-bounces@xxxxxxxxxxxxxxxxxxx 
> [mailto:ietf-behave-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
> Jonathan Rosenberg
> Sent: Tuesday, September 28, 2004 23:16
> To: 'ietf-behave@xxxxxxxxxxxxxxxxxxx'
> Subject: [Ietf-behave] port-type preservation?
> 
> 
> Folks,
> 
> An interesting thread has been going on on the mmusic list, which is 
> relevant to behave. The discussion was around NAT preservation of 
> port-types, where the types are (for UDP) "well-known" from 0 
> to 1023, 
> "registered" from 1024 to 49151, and "dynamic/private" from 49152 
> through 65535. See:
> 
http://www.ietf.org/mail-archive/web/mmusic/current/msg02902.html

If a NAT sees an outbound packet with one of these types, does it 
attempt to maintain the preservation? That is, should an outbound packet 
within the dynamic range always map to a port in the dynamic range?

I think the behave draft should probably say something about this. I 
suspect its probably a good idea to preserve the port-type.

-Jonathan R.
-- 
Jonathan D. Rosenberg, Ph.D.                600 Lanidex Plaza
Chief Technology Officer                    Parsippany, NJ 07054-2711
dynamicsoft
jdrosen@xxxxxxxxxxxxxxx                     FAX:   (973) 952-5050
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---

From: Jonathan Rosenberg <[email-masked]>
Date: Thu, 30 Sep 2004 07:52:15 -0700 (PDT)

Almost.

What I'm saying is, if the source port on the private side is in the 
dynamic range, the source port on the public side should probably be in 
that range. If the source port is in the registered range, so too should 
the source port on the public side, and same for the well-known range.

-Jonathan R.

Francois Audet wrote:

Ietf-behave@xxxxxxxxxxxxxxxxxxx 
https://list.sipfoundry.org/mailman/listinfo/ietf-behave

---

From: "Dan Wing" <[email-masked]>
Date: Thu, 30 Sep 2004 11:14:21 -0700 (PDT)

This sounds like a good idea, and it's logical.

However, do we know of any IETF or non-IETF protocol that breaks if you
don't have a source UDP port within the appropriate range?

I poked around DNS and TFTP and neither care about the source UDP port
number for their operation.  NFSv2 (RFC1831) has a preference for the
connections to come from privileged ports, but with everyone having
privileges on their own computer now-a-days I think NFS's preference is
historic.

Without an application that breaks, the best I think we should say is a
strongly-worded "MAY", like this strawman text:

  When deciding the source UDP port for an outgoing binding a NAT
  MAY choose a source port that is in the same IANA range (well
  known, registered, or dynamic) as the original source UDP port.
  However, as most modern applications to not utilize source port
  numbers as an indicator of trust, there is little value in a NAT
  to provide this function.

-d

> [mailto:ietf-behave-bounces@xxxxxxxxxxxxxxxxxxx]On Behalf Of Jonathan
> Rosenberg
> Sent: Thursday, September 30, 2004 7:52 AM
> To: Francois Audet
> Cc: 'ietf-behave@xxxxxxxxxxxxxxxxxxx'
> Subject: Re: [Ietf-behave] port-type preservation?
>
>
> Almost.
>