Hi Ramona,
you should start with the config file from http://voip-info.org/wiki/view/OpenSER+And+RTPProxy It handles NAT traversal and user location.
Thank you for your quick answer. I have a couple of questions about this configuration file.
1) I fumbled a bit through the various RFCs without - I must admit it - thorough attention, but I wasn't able to understand why record_route() should not be called with the "REGISTER" method.
2) Why fix_nated_contact() is not called in cas of a REGISTER method ? Instead fix_nated_register() is called, but I don't see the point in not fixing the Contact header field as well.
3) If loose_route() succeeds (by the way, what does the success of such a function means ?), the packet flow jumps to route[1], which is a dead-end path. This means when loose_route() is successful, we aren't going through the save/lookup magic. I have read what loose routing means in RFC3261 but I couldn't really understand what the point of this particular rule is.
Thank you for you help. Regards,