SIP/2.0 200 OK
Via: SIP/2.0/UDP nm;branch=foo;rport=26810;received=224.132.208.27
From: <sip:nm@nm>;tag=root
To: <sip:nm2@nm2>;tag=2022607222
Call-ID: 50000
CSeq: 42 OPTIONS
Allow: INVITE, ACK, OPTIONS, BYE, CANCEL, UPDATE, INFO, SUBSCRIBER, NOTIFY, MESSAGE, PRACK, REFER
Accept: application/sdp
User-Agent: V5R019C00S103
Allow-Events: dialog, message-summary, refer, reg, ua-profile
Content-Length: 0

HTTP/1.1 401 Unauthorized
WWW-Authenticate: Digest realm="realtek.com.tw", qop="auth", nonce="672bab38d24c725c1492", opaque="4eacc963"
Server: gSOAP/2.7
Content-Type: text/xml; charset=utf-8
Content-Length: 463
Connection: keep-alive