SIP/2.0 200 OK
Via: SIP/2.0/UDP nm;branch=foo;received=224.58.54.16;rport=26810
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=as7435cdc4
Call-ID: 50000
CSeq: 42 OPTIONS
User-Agent: PBX
Allow: INVITE, ACK, CANCEL, OPTIONS, PRACK, UPDATE, BYE, REFER, SUBSCRIBE, NOTIFY
Supported: replaces,timer,in-band-dtmf,100rel
Contact: <sip:171.15.159.140>
Accept: application/sdp
Content-Length: 0
