;tag=[call_number] To: Call-ID: [call_id] CSeq: [cseq] REGISTER Contact: sip:[field0]@[local_ip]:[local_port] Max-Forwards: 10 Expires: 120 User-Agent: SIPp/Win32 Content-Length: 0 ]]> ;tag=[call_number] To: Call-ID: [call_id] CSeq: [cseq] REGISTER Contact: sip:[field0]@[local_ip]:[local_port] [field2] Max-Forwards: 10 Expires: 120 User-Agent: SIPp/Win32 Content-Length: 0 ]]>