UDP Broadcasts not received on sender - Programmer

This is a discussion on UDP Broadcasts not received on sender - Programmer ; I am having trouble with UDP broadcast datagrams. I have a small VB6 test app that binds to 0.0.0.0 on port 6200. It sends a datagram to "255.255.255.255" on port 6201. There is a second socket that is bound to ...

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Thread: UDP Broadcasts not received on sender

  1. UDP Broadcasts not received on sender

    I am having trouble with UDP broadcast datagrams. I have a small VB6
    test app that binds to 0.0.0.0 on port 6200. It sends a datagram to
    "255.255.255.255" on port 6201. There is a second socket that is bound
    to port 6201 on the same address. All computers receive this datagram
    except for the computer which sent it. FYI the computer is running
    Windows XP SP2 v.2149

    If I run this same application on any other computer on the network
    (even Windows Vista), the sending computer receives the datagram it
    has broadcast, so the problem is confined to only one computer.

    I have tried the same example in C# as well, so the problem is
    definitely on a lower level. Just to be clear specifically sending to
    the IP address of any interface on the machine does work and the
    message is received, it just does not receive broadcast messages it
    has sent itself. It also received broadcast messages sent from another
    computer.

    Incidentally, the problematic computer does receive its own broadcast
    messages only while I am running Ethereal/Wireshark in packet
    capturing mode. I have told that this is because Ethereal switches the
    interface over to promiscuous mode. Indeed, coding the extra bit to
    put the interface into promiscuous mode in my C# example does make the
    example work.

    I have disabled the network card and plugged in a Wifi adapter,
    thinking it be the network causing the problem, but the results are
    the same. Also, all the computers are running more or less the same
    software and firewall(ZoneAlarm) so its not that either.

    Why is only on this one computer that it doesn't work?

  2. Re: UDP Broadcasts not received on sender

    Don't worry, got it. Turns out that the computer had the latest
    version of Kaspersky installed which also install "Kaspersky Anti-
    Virus NDIS Filter". Disabling this and restarting the network adapter
    solved the problem.


    On Apr 3, 11:34 am, riaancil...@gmail.com wrote:
    > I am having trouble with UDP broadcast datagrams. I have a small VB6
    > test app that binds to 0.0.0.0 on port 6200. It sends a datagram to
    > "255.255.255.255" on port 6201. There is a second socket that is bound
    > to port 6201 on the same address. All computers receive this datagram
    > except for the computer which sent it. FYI the computer is running
    > Windows XP SP2 v.2149
    >
    > If I run this same application on any other computer on the network
    > (even Windows Vista), the sending computer receives the datagram it
    > has broadcast, so the problem is confined to only one computer.
    >
    > I have tried the same example in C# as well, so the problem is
    > definitely on a lower level. Just to be clear specifically sending to
    > the IP address of any interface on the machine does work and the
    > message is received, it just does not receive broadcast messages it
    > has sent itself. It also received broadcast messages sent from another
    > computer.
    >
    > Incidentally, the problematic computer does receive its own broadcast
    > messages only while I am running Ethereal/Wireshark in packet
    > capturing mode. I have told that this is because Ethereal switches the
    > interface over to promiscuous mode. Indeed, coding the extra bit to
    > put the interface into promiscuous mode in my C# example does make the
    > example work.
    >
    > I have disabled the network card and plugged in a Wifi adapter,
    > thinking it be the network causing the problem, but the results are
    > the same. Also, all the computers are running more or less the same
    > software and firewall(ZoneAlarm) so its not that either.
    >
    > Why is only on this one computer that it doesn't work?



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