[Asterisk-Users] STUN and Asterisk

[Chris Albertson]

OK, I've breifly looked at STUN and what it is and can do.
First off it is NOT a way to punch UDP through a firewall.
STUN offers a method to determine the firewall environment
and find out just what is "out there". But leaves it to
Asterisk to determine what to do. 

The way it could be used within Asterisk:

You would link in the STUN client library from www.vovida.org/
and then when Asterisk first fires up it would call the STUN
library to see what kind, if any fire wall is up.  It would
store this information globally.

Later inside chan_sip.c Asterisk could set up the packets
"correctly" with pulic IP address if required.

This would be VERY much like the two current patches do except
that we would no longer need the new lines in sip.conf as STUN
would figure this out for us.  

The other thing we could do is detect "hopeless" caes and
rather then let the audio fall on the floor we could issue
an error message saying something like UDP is 100% blocked
no way to make this call" and not even attemp it.

Bottom line:  STUN could save the user much configuration
hassel but does noting that a very knowagable person could
not figure out and then put into a *.conf file.  But most
people don't know if their NAT firewall for "symetric" for
"restricted cone".  STUN can figure this out automatically.

Notice that xten X-Lite already does the above.



=====
Chris Albertson
  Home:   310-376-1029  chrisalbertson90278 at yahoo.com
  Cell:   310-990-7550
  Office: 310-336-5189  Christopher.J.Albertson at aero.org
  KG6OMK

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