Frame 1763 (449 bytes on wire, 449 bytes captured)
Internet Protocol, Src Addr: vocal.engdomain.com (10.250.250.202), Dst Addr: 10.200.1.4 (10.200.1.4)
User Datagram Protocol, Src Port: 5060 (5060), Dst Port: 5060 (5060)
Session Initiation Protocol
    Status line: SIP/2.0 407 Proxy Authentication Required
        Status-Code: 407
    Message Header
        Via: SIP/2.0/UDP 10.200.1.4:5060;branch=z9hG4bK-3k6oqlesj2mi
        To: <sip:1142@vocal.engdomain.com>;tag=a83de056
        From: "jringle" <sip:jringle@10.250.250.202>;tag=24th1b497c
        Call-ID: 3c41defa1e61-otf1blzfc8ak@10.200.1.4
        CSeq: 1 INVITE
        Proxy-Authenticate: Digest algorithm=MD5,domain="10.250.250.202",nonce="1057382941",realm="10.250.250.202"
        Content-Length: 0