SIP/2.0 404 Not Found
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=b686e968-624a204d-13c4-5506-71a643-2477151-71a643
Call-ID: 50000
CSeq: 42 OPTIONS
User-Agent: Epicentro - YAPS ADB Stack
Supported: replaces,timer,100rel
Via: SIP/2.0/UDP nm;received=224.208.157.5;rport=26810;branch=foo
Content-Length: 0

HTTP/1.1 401 Unauthorized
Server: YAPS
WWW-Authenticate: Digest realm="YapsieWorld", qop="auth", nonce="1479e835edafd5e145a79ed0094c5d3c", opaque="cf33f33a310f4be5b5204a330bfa6e10"
Content-Length: 0
Connection: close