[Serusers] NAT & RTPPRoxy

[Gary Brewer]

Hi,

I have come across a similar problem. I want to use the A/V facilities of
Windows Messenger if one or both of my clients are behind a NAT. I realise
that it seems to be impossible to get this to work if the NAT is symmetric.
(See: RFC3489 "Applicability Statement")

If only one of my clients is behind a NAT then it would seem I would have to
communicate my NATs external address and port mapping to the non-NAT'd
client (possibly with the help of STUN) in my SIP Invite SDP message. I
would also have to setup UDP mappings for SIP, RTP/RTCP Audio Video on my
NAT. Are my A/V port mappings also included in the Invite SDP message?

If both clients are NAT'd then what is the approach? I don't see how I
register with the SIP server using an external NAT address (my guess is this
is what I would have to use if I wanted anyone on the other side of the NAT
to be able to see me). MSFT have seemed to got around this problem by
recommended everyone to use uPnP enabled NATs, which will automatically bind
to an external address on the NAT and, I assume, use this when they register
with the SIP server.

RTPProxy is here https://demo.portaone.com/~sobomax/PortaSIP/ how does
RTPProxy help in the NAT situation, does it at all?

Please correct me where I am wrong, I am still trying to get my head around
all of this! Has anyone successfully been able to get any of the scenarios
above working (with AV)?


Regards,

Gary Brewer



-----Original Message-----
From: Jan Janak [mailto:jan at iptel.org] 
Sent: 03 September 2003 00:35
To: Dan Fernandez
Cc: serusers at lists.iptel.org
Subject: Re: [Serusers] No audio

Hello,

is one (or both) phones behind a NAT ? If so you will need to configure
your nat to let the media traffic through.

If not, then we will need more information.

  Jan.

On 02-09 18:55, Dan Fernandez wrote:
> Greetings from So. America!
> 
> I just begun playing with SER.  So far I can place calls within a LAN. I
> have SER running on a box, with one public and one private IP.  My problem
> right now is that if I try to call from a UA connected via a dialup, there
> is no audio in either end. The setup of the call seems fine (the phones
ring
> OK). I have disable the firewall and still no luck. Do I need to install
> rtpproxy? Where can I download it?(the links I´ve seen don´t work)
> 
> Any help would be greatly appreciated.
> 
> Rgds
> Dan
> 
> _______________________________________________
> Serusers mailing list
> serusers at lists.iptel.org
> http://lists.iptel.org/mailman/listinfo/serusers

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