Subject: Re: [Sip] Solutions to NAT: STUN

From: Álvaro Canivell García de Paredes<[email-masked]>
Date: Wed, 08 Feb 2006 14:11:26 +0100

Found out the following:

Sip-communcator makes use of stun4j implementation of STUN. This 
implementation, at least the last CVS, can discover de NAT type 
(Discovery Process in rfc3849)(i have port restricted cone NAT), and 
also discover the public address of the client (Binding Acquisition in 
rfc3849), from the client that is behind a NAT.

However, it doesn't implement Binding Lifetime Discovery (rfc3849). That 
is usefull if thje client needs to refresh the NAT bindings from time to 
time.

With the current implementation of stun4j,  I can send out of the NAT 
SIP messages with the public IP address in the contact, and media 
specification (in case of SDP usage). But requests coming from outside 
into the NAT, are NOT ALWAYS routed into the client. I guess this is 
because the bindings in the NAT are deleted, after some time.

Any idea on how to keep bindings alive, any roundabout method?

Álvaro

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---

From: Álvaro Canivell García de Paredes<[email-masked]>
Date: Wed, 08 Feb 2006 18:00:29 +0100

Sorry, there was a typo in my message, the RFC is 3489, not 3849.

Álvaro

Álvaro Canivell García de Paredes wrote:

> However, it doesn't implement Binding Lifetime Discovery (rfc3849). 
> That is usefull if thje client needs to refresh the NAT bindings from 
> time to time.
>
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