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Old 05-21-2009, 06:33 AM   #1
nitinarora
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Registered: Apr 2009
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SYN, SYN_ACK but no ACK


Hi,

I am trying to setup the network interface on a fresh board. I have compiled a fresh kernel and inserted ethernet drivers.
I brought the interface up through ifconfig command and now I can ping from board to my PC and also from PC to board both ways.

Board and PC are connected back to back through an ethernet cable

Board <---------> PC

Now I have run a simple TCP Echo client on the board and TCP Echo Server on the PC. TCP client which is running on the board while "connect" system call fails with "Time out" error code.

I have captured the ethereal traces and found that SYN, SYN_ACK are being exchanged but no ACK is returned by the TCP client running on the board.

The same TCP echo client works fine when run on some other Linux PC machine and is able to connect with the echo server running on my PC.

Kindly suggest what could be the probable reason for this on the fresh board.

Thanks

Last edited by nitinarora; 05-21-2009 at 06:34 AM.
 
Old 05-21-2009, 06:31 PM   #2
nini09
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Registered: Apr 2009
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The SYN_ACK should be checked, such as sequence number, port number. Maybe echo client doesn't recognize the SYN_ACK. If you can port ethereal trace, that's great.
 
  


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