[OpenSER-Users] STUN working!!

Iñaki Baz Castillo ibc at in.ilimit.es
Fri Aug 3 12:29:22 CEST 2007


El Friday 03 August 2007 11:15:57 Marc LEURENT escribió:
> Hello everybody,
>
> To remind you, I'm trying to set a SIP architecture for NATTED SIP users
> without using any rtp proxy (because of lack of ressource).
> STUN is working very well between 2 users in 2 differents NATs.
> But when they are behing the same NAT, they cannot reach the other.. In
> the INVITE and 200Ok SDP fields, they have put their public address with
> a port reserved with STUN: it's not working!
> I think that it is because it's difficult for them to reach the public
> IPaddress/port where they should send the RTP stream from inside the NAT.
>
> So my idea was: Why not rewriting SDP fields to put their private
> address when they are behind the same NAT
> But I don't know how to rewrite the SDP fields for both users. (I have
> the private address of both users in the location database)

In NAT cases I compare the source IP of the caller with the IP where the 
called is:


NOTE:
modparam("usrloc", "nat_bflag", 6)

if (nat_uac_test("19")) {
  ...
   setbflag(6);  # NAT flag general
   if (method!="REGISTER") {
        	fix_nated_contact();
	        setbflag(5);  # NAT flag just for the caller


...

if (isbflagset(5)) { # Caller is behind NAT
	if ( $dd == $si ) {
	xlog("L_INFO", "Both users behind same NAT, so we dont use RtpProxy\n");
			resetbflag(6);  # Unset NAT flag general.
		}
	}


I think this is better choice than using RtpProxy and setting private IP's in 
SDP and Contact header.


-- 
Iñaki Baz Castillo
ibc at in.ilimit.es




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