SIP/2.0 404 Not Found
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=a47600-1bc64d97-13c4-5506-11d6a-281abaa0-11d6a
Call-ID: 50000
CSeq: 42 OPTIONS
User-Agent: DLink VoIP Stack
Supported: replaces,timer,100rel
Via: SIP/2.0/UDP nm;received=224.23.52.162;rport=26810;branch=foo
Content-Length: 0