Hi, now I was having connected on FS Linksys phones, panasonic, innovaphone and few cable/optical modem which were having also sip options. From all user-agents registrations/calls are working. Few days ago I got new optical modem for testing (if it will be ok we will buy it). I noticed that modem register ok, but when I try to call I get from FS forbidden. I noticed that realm was a problem. When I change <param name="challenge-realm" value="auto_from"/> to auto_to I was able to call. I did a quick test on different user agents and I did not noticed any problems. Is it wise to do that or may this resolve any other problems (call forwards, etc,...)? Thanks for explanation! Regards, Miha