Subject: Netmeeting - NAT issue

From: "Vivek Gupta" <[email-masked]>
Date: Tue, 12 Mar 2002 16:48:10 -0500

Hi
I have been bugging U guys a lot for long now ..... especially Hari

OK here is another question quite similar to previous one:

Net meeting by Microsoft is not suppoted by NAT ..... this is the major problem 

--this is a problem with NAT or with NET meeting.??

I think I should rephrase my query ...wait

--Is it that the net meeting doesn't support NAT .... or the NAT doesn't support netmeeting.??

I know that Net Meeting doesn't work with NAT ..... but where exactly is the problem .......with NAT or with netmeeting

attached is my network set up

thanx
Vivek

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From: Randy Bush <[email-masked]>
Date: Tue, 12 Mar 2002 14:43:10 -0800

> Net meeting by Microsoft is not suppoted by NAT ..... this is the major

you may not have noticed that
  o there is no ietf standards track document for net meeting
  o there is no ietf standards track document for nat

hence no one here is surprised.  caveat emptor.

we design and build the information superhighway.  we can not repair
you car.

randy

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From: Keith Moore <[email-masked]>
Date: Tue, 12 Mar 2002 17:56:34 -0500

> Net meeting by Microsoft is not suppoted by NAT ..... this is the major

NATs violate many of the assumptions of the Internet Protocol.  It's 
unrealistic to expect many kinds of IP applications to work in the 
presence of NATs,  unless they were specifically designed to do so.
And while it might seem desirable to make all applications NAT-tolerant,
NAT-tolerant design often imposes significant barriers to the 
performance and scalability of applications, and (due to the need 
for intermediaries to tunnel through NATs) to deployment of such 
applications.

Keith

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From: "Jose Manuel Arronte Garcia" <[email-masked]>
Date: Tue, 12 Mar 2002 17:03:58 -0600

Hi Vivek:

    I am behind a firewall, as Help-desk Mgr. we had to find some answers for our customers regarding the issues you ask. I am SURE the problem is with netmeeting and other MS comunications softwatre. Try the following links:

http://messenger.msn.com/support/knownissues.asp

http://r450.voice.microsoft.com/netinfo.asp?NAT=yes&PLCID=0c0a&Version=4.5&CLCID=080a&BrandID=MSMSGS&country=MX

http://messenger.microsoft.com/ES/support/helphome.asp?client=1#Q3b

the problem is with Netmeeting, not with NAT.

Saludos.
Regards.
____________________________________________________
José Manuel Arronte García
Supervisor de Soporte Técnico Helpdesk

Meg@Red Veracruz
Operadora MegaCable S. A. de C. V.
Av. S. Díaz Mirón 2625-A
Fracc. Moderno 91916
Veracruz Ver. MÉXICO

+52 (229) 923-0400, 923-0410 ext. 5
http://www.megacable.com.mx/
http://www.megared.net.mx/

____________________________________________________
"Who's the more foolish, the fool, or the fool who follows him?".
 --O. W. Kenobi (in Star Wars ep.IV: A New Hope)

  ----- Original Message ----- 
  From: Vivek Gupta 
  To: [email-masked] 
  Sent: Tuesday, March 12, 2002 3:48 PM
  Subject: Netmeeting - NAT issue

  Hi

  thanx
  Vivek

---

From: Joe Touch <[email-masked]>
Date: Tue, 12 Mar 2002 15:17:35 -0800

> --this is a problem with NAT or with NET meeting.??

Anything that works with regular IP addresses and breaks with IP 
addresses (as you describe in your figures), is, by definition, the NAT 
breaking.

> --Is it that the net meeting doesn't support NAT .... or the NAT doesn't 

NAT doesn't support Netmeeting. It uses H.323 encoding, which uses IP 
addresses and dynamically assigned ports in-band (inside the 
connection). The NAT is translating the outer IP addresses, but because 
your NAT doesn't understand H.323, it doesn't know it would have to also 
translate the inner addresses and ports. Netmeeting expects that it can 
dynamically select a port to use to connect back to your machine, but 
that defeats what a NAT "thinks" the Internet looks like (notably 
because it's incorrect).

The best solution: get real IP addresses. It's cheaper than wasting your 
time figuring out why things don't work.

Joe

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From: Lloyd Wood <[email-masked]>
Date: Wed, 13 Mar 2002 17:39:02 +0000 (GMT)

On Tue, 12 Mar 2002, Keith Moore wrote:

> NATs violate many of the assumptions of the Internet Protocol.

actually, NATs violate the prime directive that is the Principle of
Minimum Intervention - in essence, don't mess with stuff that's none
of your business and is just passing through.

L.

<[email-masked]>PGP<http://www.ee.surrey.ac.uk/Personal/L.Wood/>

---

From: Andrew McGregor <[email-masked]>
Date: Mon, 18 Mar 2002 12:34:05 +1200

Or, get a NAT which *does* connection-track H.323.  They do exist, 
open-source and not, and work just fine.

Better, get a proper H.323 gateway (which will work behind an H.323 aware 
NAT if done properly) so people can call in as well as out.

However, NAT is still brokenness. (and so is H.323)

Andrew

--On Tuesday, March 12, 2002 15:17:35 -0800 Joe Touch <[email-masked]> wrote:

> addresses and dynamically assigned ports in-band (inside the connection).
> The NAT is translating the outer IP addresses, but because your NAT
> doesn't understand H.323, it doesn't know it would have to also translate
> the inner addresses and ports. Netmeeting expects that it can dynamically
> select a port to use to connect back to your machine, but that defeats
> what a NAT "thinks" the Internet looks like (notably because it's
> incorrect).
>