question about ethernet NIC

This is a discussion on question about ethernet NIC within the Networking/Device Communication forums, part of the General Programming Boards category; hello . I am working on a AVR board that can connect to ethernet and knows ping ,ARP,UDPand TCP packets ...

  1. #1
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    question about ethernet NIC

    hello .
    I am working on a AVR board that can connect to ethernet and knows ping ,ARP,UDPand TCP packets .
    almost each time I connect the board to my PC NIC the NIC starts sending packet ( 180 packets in 3 mins). I checked protocol part of recieved packets , it is 11(udp) in most of them .
    do you know why NIC do that ?
    how can I stop it ?

    my NIC is comexrl2000

    thank you

  2. #2
    * Death to Visual Basic * Devil Panther's Avatar
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    I checked protocol part of recieved packets , it is 11(udp) in most of them .
    Can you please explain, are you saying that you only receive 11 udp packets? if so what are the rest?
    "I don't suffer from insanity but enjoy every minute of it" - Edgar Allen Poe

    http://www.Bloodware.net - Developing free software for the community.

  3. #3
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    no I meant 13th byte of recived packets has value = 11 . and it is for most of recived packets .
    there is some ping and ARP between them too that the board replys them .

  4. #4
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    Let me see if I understand want you want to do.
    Your NIC sends packets and you wish to stop it, right?!

    I guess the best way to do so is to block each and every outgoing connection at the application level, before it reachs the NIC (the datalink layer) - I suggest a FireWall, any FW you can install on the OS you are running the tests from.
    "I don't suffer from insanity but enjoy every minute of it" - Edgar Allen Poe

    http://www.Bloodware.net - Developing free software for the community.

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    I think if I do that then I cant test my board .
    I need the NIC packets but not stuff packets , how can I stop sending of these stuff packets ?

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    why not check with sniffer on your PC. It will tell you what packet it is (if it can decode it correctly).

  7. #7
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    Quote Originally Posted by arian
    I think if I do that then I cant test my board .
    I need the NIC packets but not stuff packets , how can I stop sending of these stuff packets ?
    I don't agree, you can allow some applications to connect the network, just play with the FW configuration.
    "I don't suffer from insanity but enjoy every minute of it" - Edgar Allen Poe

    http://www.Bloodware.net - Developing free software for the community.

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    hello .
    can you plz explain more about working with fire wall . I haven't work with any of them till now and dont know what I have to do at all .(I use win XP)
    and
    I haven't packet sniffer and it is holiday in my country today and no computer shop is open .
    is it possible for packet sniffers to give them bytes of packets and it says what kind of packet it is ?
    My NIC starts sending of packets imediately after I connect the AVR board to it .
    usually it stops after about 10 mins but I dont know why it doesnt stop today and aslo I had this problem last night .
    can you plz help me ?
    it is bytes of packets the AVR board recieves :
    bold bytes in UDP_data are same in all recived packets
    byte 1-6 : EthernetPacketDest = FF-FF-FF-FF-FF-FF
    byte 13-14 : EthernetPckeTtype = &H0800
    byte 15 : Ip_vers_len = &H45
    byte 16 : TOS = 00
    byte 17-18 : Ip_pktlen = &H004E = 78(decimal)
    byte 21 : IP_flags = 00
    byte 22 : Ip_offset = 00
    byte 23 : Ttl = &H80
    byte 24 : Ip_protocol = &H11
    byte 31-34 : Ip_destaddr = C0-A8-01-FF
    byte 35-36 : Udp_srcport = &H0089 = 137(decimal)
    byte 37-38 : Udp_destport = &H0089 = 137(decimal)
    byte 39-40 : Udp_len = &H003A = 58(decimal)
    byte 43-92 : Udp_data =
    87 0F 01 10 00 01
    00 00 00 00 00 00 20 45
    4F 46 44 43 4F 46 4A 45
    42 45 49 45 50 45 50 43
    4F 45 44 45 50 45 4E 43
    41 43 41 43 41 41 41 00
    00 20 00 01


    thank you

  9. #9
    * Death to Visual Basic * Devil Panther's Avatar
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    I haven't packet sniffer and it is holiday in my country today and no computer shop is open .
    I suggest you download Ethereal packet sniffer, for free

    As for a firewall, I suggest you use ZonaAlarm, also for free
    Once the FW is installed, it will ask you if you wish to allow the applications to connect the network, if you denie them of this right they will not be able to send packets through the NIC.
    (NOTE: once you remove the FW the restrictions will be gone.)

    If you have anymore questions about the packet sniffer or the firewall setup, you are welcome to contact me via messenger: devil_panther@hotmail.com


    GoodLuck.
    "I don't suffer from insanity but enjoy every minute of it" - Edgar Allen Poe

    http://www.Bloodware.net - Developing free software for the community.

  10. #10
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    I found the answer maybe you like to know it too .
    protocol =UDP
    src port = dest port = 137
    it is NetBios NAME service (NNS)
    I disabled it and the NIC stoped sending of that packet .

  11. #11
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    Well you are running windows... but I'm sure you have other applications running that might interrupt with the tests... it's your choise.
    "I don't suffer from insanity but enjoy every minute of it" - Edgar Allen Poe

    http://www.Bloodware.net - Developing free software for the community.

  12. #12
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    thank you but I have installed a packet sniffer and after disabeling of NNS there is no packet except the packets I sent to / from the board .

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