[Users] x-lite and nat_uac_test(16)

Alexander Bergolth leo at strike.wu-wien.ac.at
Fri May 18 14:18:34 CEST 2007


Hi!

I've noticed that (at least on my boxes) x-lite uses a different
source-port for the sip-connection than the one that is announced in the
Via-header. (See the example below.)

This behavior results in nat_uac_test(16) always reporting that the
client is behind a NAT.

Can anyone confirm this behavior? Is it a bug in X-Lite or is there any
good reason for it?

Cheers,
--leo

-------------------- 8< --------------------
No.     Time        Source                Destination           Protocol
Info
      4 0.000808    137.208.90.164        137.208.89.45         SIP
 Request: REGISTER sip:wu-wien.ac.at

Frame 4 (640 bytes on wire, 640 bytes captured)
Ethernet II, Src: DellEsgP_85:83:ea (00:0b:db:85:83:ea), Dst:
Cisco_f3:2e:80 (00:0d:29:f3:2e:80)
Internet Protocol, Src: 137.208.90.164 (137.208.90.164), Dst:
137.208.89.45 (137.208.89.45)
Transmission Control Protocol, Src Port: 1831 (1831), Dst Port: 5060
(5060), Seq: 1, Ack: 1, Len: 586
    Source port: 1831 (1831)
    Destination port: 5060 (5060)
    Sequence number: 1    (relative sequence number)
    [Next sequence number: 587    (relative sequence number)]
    Acknowledgement number: 1    (relative ack number)
    Header length: 20 bytes
    Flags: 0x18 (PSH, ACK)
    Window size: 1028096 (scaled)
    Checksum: 0x491e [correct]
Session Initiation Protocol
    Request-Line: REGISTER sip:wu-wien.ac.at SIP/2.0
    Message Header
        Via: SIP/2.0/TCP
137.208.90.164:1676;branch=z9hG4bK-d87543-bd24cf102007467f-1--d87543-;rport
        Max-Forwards: 70
        Contact:
<sip:30001 at 137.208.90.164:1676;rinstance=7ce462f932219953;transport=TCP>
        To: "Alexander Bergolth"<sip:30001 at wu-wien.ac.at>
        From: "Alexander Bergolth"<sip:30001 at wu-wien.ac.at>;tag=b904b134
        Call-ID: N2VjNGQxYzZlOWNiYWU5OTMwNzQ4OTZkMWU3NmRkYTE.
        CSeq: 1 REGISTER
        Expires: 3600
        Allow: INVITE, ACK, CANCEL, OPTIONS, BYE, REFER, NOTIFY,
MESSAGE, SUBSCRIBE, INFO
        User-Agent: X-Lite release 1006e stamp 34025
        Content-Length: 0
-------------------- 8< --------------------

-- 
e-mail   ::: Alexander.Bergolth (at) wu-wien.ac.at
fax      ::: +43-1-31336-906050
location ::: Computer Center | Vienna University of Economics | Austria





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