SIP/2.0 200 OK
Via: SIP/2.0/UDP nm:5060;branch=foo;rport=26810;received=224.182.155.69
To: <sip:nm2@nm2>;tag=dWaj6xO18nxNar
From: <sip:nm@nm>;tag=root
Call-ID: 50000
CSeq: 42 OPTIONS
Max-Forwards: 70
User-Agent: MTK
Content-Length: 0