[Serusers] how can we setup ser to route invite packet?

Hi, My enviroment is like this: phone1---proxy1-----proxy2-----phone2. phone1 register to proxy1, and phone2 register to proxy2, now I initiate call from phone1 to phone2, I noticed that phone1 just resolved proxy2's domain by itself and send invite to proxy2 directly, everything works fine. My question is : How can I force phone1 to send invite to proxy1 and then let proxy1 to route that invite packet to proxy2? Actually, I hope all packet between phone1 and phone2 can go through proxy1 and proxy2, include RTP. This behaviour was determined by phone's configuration or proxy's configuration? I'm using ser 0.9.6 works as proxy and linphonec works as phone. I also tried to use asterisk works as proxy but got same result. Thanks in advance. -- Rgds, Hans Yin Email: hansyin(a)gmail.com MSN: hansyin(a)hotmail.com Skype: hans_yin_vancouver