;tag=[call_number] To: Call-ID: [call_id] CSeq: 1 REGISTER Contact: sip:[field0]@[local_ip]:[local_port] Max-Forwards: 5 Expires: 1800 User-Agent: SIPp/Linux Content-Length: 0 ]]> ;tag=[call_number] To: Call-ID: [call_id] CSeq: 2 REGISTER Contact: sip:[field0]@[local_ip]:[local_port] [field2] Max-Forwards: 5 Expires: 1800 User-Agent: SIPp/Linux Content-Length: 0 ]]> ;tag=[call_number] To: Call-ID: [call_id] CSeq: 1 REGISTER Contact: sip:[field0]@[local_ip]:[local_port] Max-Forwards: 5 Expires: 0 User-Agent: SIPp/Linux Content-Length: 0 ]]> ;tag=[call_number] To: Call-ID: [call_id] CSeq: 2 REGISTER Contact: sip:[field0]@[local_ip]:[local_port] [field2] Max-Forwards: 5 Expires: 0 User-Agent: SIPp/Linux Content-Length: 0 ]]>