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  1. #1

    Not receiving UDP data


    This is the issue:

    First the setup

    System A - WIN XP
    System B - Fedora 9

    A and B is connected via a wireless DSL router.

    ipconfig on A shows the following:
    IP Address -
    Subnet Mask -
    Default Gateway -

    ifconfig on B shows the following:

    eth0 Link encap:Ethernet HWaddr 00:1D:72:FC:64:78
    inet addr: Bcast: Mask:
    inet6 addr: fe80::21d:72ff:fefc:6478/64 Scope:Link
    RX packets:2702 errors:0 dropped:0 overruns:0 frame:0
    TX packets:2985 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:1000
    RX bytes:1864292 (1.7 MiB) TX bytes:658219 (642.7 KiB)

    lo Link encap:Local Loopback
    inet addr: Mask:
    inet6 addr: ::1/128 Scope:Host
    UP LOOPBACK RUNNING MTU:16436 Metric:1
    RX packets:4784 errors:0 dropped:0 overruns:0 frame:0
    TX packets:4784 errors:0 dropped:0 overruns:0 carrier:0
    collisions:0 txqueuelen:0
    RX bytes:245304 (239.5 KiB) TX bytes:245304 (239.5 KiB)

    A UDP application trying to send test data from A to B (port 5060). The receiver at B is not getting the data.

    I used analyser at B (wireshark)..which shows data is coming to B ( but strangely the UDP application is not receiving the same.

    To debug I ran this test:

    Instead of A sending UDP data to B, I ran the sender application in B itself - this time the receiver app in B got the data.

    The data is going through localloop instead of routing it via, though the applicatios are binded to IP:

    If I disable the lo - then the receiver does not get any data.

    I am perplexed - any hints. It seems there is something wrong in the network configuration perhaps.


  2. #2
    Linux Guru Lazydog's Avatar
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    Firewall running on host B?


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