Frame 2 (455 bytes on wire, 455 bytes captured)
Internet Protocol, Src Addr: 10.250.250.202 (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-ifrhdh6dk79v
        To: <sip:1416@10.250.250.202;user=phone>;tag=c79d8c92
        From: "jringle" <sip:jringle@10.250.250.202>;tag=y15w2v0hsd
        Call-ID: 3c41dede1ca4-hbbht6cxjl7v@10.200.1.4
        CSeq: 1 INVITE
        Proxy-Authenticate: Digest algorithm=MD5,domain="10.250.250.202",nonce="1057078835",realm="10.250.250.202"
        Content-Length: 0