A year on, I thought I’d give it another try. I have a Sipura 1001 connected to a the Internet through a Netgear WGR614, all configured for Sipgate.
The trickiest part was to configure the router. Automatic routing didn’t work, so I had to create a port forwarding table. What confused me for the longest time was that the instructions on the Sipgate website were incorrect, at least for my configuration. The Sipgate website mentioned the wrong RTP-Ports. They listed UDP 5004 for UDP, but by logging into the Sipura’s web interface, I found out that there was actually a range for UDP, from 16384 – 16482. Strange.
Anyway, if you are in a similar situation, I strongly recommend to check the device’s interface to find the proper ports to be forwarded.