The French ISP Free provide TV over DSL. Some of the channels could be directly seen on a computer through the RTSP protocol. However it is not something that is working nicely through a home switch that is just behind the FreeBox DSL router like an OpenWRT running box.
Several solution exist on the net however major part of them required static
port forwarding linked with configuration of VLC (The recommended client). Here
we will see how to allow it without all this strong and static configuration
with the help of two kernel module that will track the RTSP connexion, open the
correct port in the firewall and routes the packet to the VLC client. These two
modules are ip_nat_rtsp et ip_conntrack_rtsp
To process only the kmod-ipt-nathelper-extra package need to be
installed on the OpenWRT box. Do either through the web interface or through ssh
with the help of opkg. After installation check that the two requiered
modules are loaded with the two following commands on the OpenWRT box:
insmod ip_conntrack_rtsp
insmod ip_nat_rtsp
If its answer that insmod: a module named ip_nat_rtsp already exists, it
means that the module is already loaded.
Now you just have to launch you preferred player and start watching.