SIP/2.0 200 OK
Via: SIP/2.0/UDP nm;branch=foo;rport=26810;received=224.29.212.83
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=1237603965
Call-ID: 50000
CSeq: 42 OPTIONS
Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, SUBSCRIBE, NOTIFY, INFO, UPDATE
Accept: application/sdp
User-Agent: MA131 SIP-stdR11448 2.0.22_20200709 131UK88102778
Content-Length: 0