I've now tried installing the Linux Internet Gateway Device upnpd daemon on sol.

No UPnP shows up on my Win XP machine, even after reboot of the XP machine.

The problem is that the web page that the UPnP server exposes (on the style of http://172.16.1.11:49152/gatedesc.xml) is firewalled on the linux box.

Why doesn't the IGD/libupnp manage to add firewall rules to let packets through?

This page seems to have some possible solutions: http://gentoo-wiki.com/HOWTO_Setup_UPnP_with_IPTables

I have problems with the firewall under Linux and my SIP application.

I think there are three ways around it:

1. Try to get Netfilters/conntrack sip / rtp to work
2. Install UPNP on the server, and get the client to use UPNP to open RTP ports etc

Maybe option two is the cleanest?

There is a UPnP client library here: http://pupnp.sourceforge.net/

Server stuff is in a package called Linux Internet Gateway device, I think.

Solved the Sofia SIP ACK problem.

It went away when I added ';transport=udp' at the end of the NUTAG_URL.

The problem now seems to be that the incoming RTP stream is not reaching the application. Do I remember something about this might work if I receive and send RTP using the same port I receive data on?