In my search for help, I came around this mail from Paul (Java Rockx) http://archivum.info/serusers@lists.iptel.org/2004-11/msg00608.html with the attached configuration file http://archivum.info/serusers@lists.iptel.org/2004-11/bin00015.bin In the NAT TEST section you have " if (method=="REGISTER") { fix_nated_register(); ..." Where is this function "fix_nated_register()" from..!! NB: I'm using ser.0.8.14 and gets error trying to load that function. Regards.