[OpenSIPS-Users] Why does NAT keepalive only work for UDP?

Klaus Darilion klaus.mailinglists at pernau.at
Wed Nov 12 12:21:28 CET 2008

Dan Pascu schrieb:
> Man, you have a lot of questions today... :P
> On Wednesday 12 November 2008, Iñaki Baz Castillo wrote:
>> Hi, I wonder why SIP keepalive method (sending a NOTIFY/OPTIONS
>> perdiodically) just works for UDP, this is: why the request is not sent
>> via TCP?
> Mainly I guess it's because nobody did implement it, as none had a need 
> for it yet? Add to that that the TCP stack is handled differently (inside 
> opensips) and it's a complex beast which is not easy to tap into as it is 
> with UDP. Also, I guess historical reasons was also a factor as it was 
> meant as an improved replacement for the (UDP only) solutions in the 
> nathelper and mediaproxy modules (which it is). While being improved it 
> doesn't imply it has to be perfect, so if you need TCP support, you are 
> wellcome to implement it and share it with us ;)

and make it non-blocking ;-)

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