[OpenSER-Users] nat_uac_test("31") not enough to detect with some consumer voip passthrough routers

[Mike Fedyk]

Hi,

Some of our customers have been connecting behind NAT routers that mangle
the sip headers but don't keep the ports open.  I've added checks on the
source port to catch this case.  Has anyone done something similar or
better?  It'd be nice if this could be added as a flag to nat_uac_test() if
it is a common test and there isn't already a better way.

Here is the code I've used to handle my registers.  I need to do more
testing once I can get some of these routers in my lab to see how this
affects call processing, not just registering.

Mike

	if (!search("^Contact:\ +\*") && nat_uac_test("7"))
	{
		xlog("L_INFO", "M=$rm RURI=$ru F=$fu IP=$si:$sp CS=$cs
route2: matched nat_uac_test7\n");
		xlog("L_NOTICE", "M=$rm RURI=$ru F=$fu IP=$si:$sp CS=$cs
route2: setbflag(6)\n");
		setbflag(6);
		xlog("L_NOTICE", "M=$rm RURI=$ru F=$fu IP=$si:$sp CS=$cs
route2: fix_natted_register()\n");
		fix_nated_register();
		#xlog("L_INFO", "M=$rm RURI=$ru F=$fu IP=$si:$sp CS=$cs
route2: force_rport()\n");
		#force_rport();
	};
	#Some NAT devices modify SIP headers to but do not keep the port
mappings open, also some UAs detect report the 
	#public IP address.  In both cases we need nat ping.  Exceptions for
default ports.  These ports if used as 
	#source ports can be assumed to be at the very least port forwarded.
	if (!isbflagset(6) && $sp != '5060' && $sp != '5061')
	{
		xlog("L_NOTICE", "M=$rm RURI=$ru F=$fu IP=$si:$sp CS=$cs
route2: matched !isbflagset(6) && ($sp != '5060' && $sp != '5061')\n");
		setbflag(6);
	};