Kenneth Furge(deleted)
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Re: io-pkt dropping syn-ack frame with data payload
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Kenneth Furge(deleted)
03/22/2010 5:35 PM
post50185
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Re: io-pkt dropping syn-ack frame with data payload
Attached is a tcpdump capture of a successful connection with a Linux client (I could not attach two files to the first
posting).
- K.C.
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Sean Boudreau(deleted)
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Re: io-pkt dropping syn-ack frame with data payload
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Sean Boudreau(deleted)
03/22/2010 5:45 PM
post50187
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Re: io-pkt dropping syn-ack frame with data payload
On Mon, Mar 22, 2010 at 05:33:31PM -0400, Kenneth Furge wrote:
> We're using QNX to setup a TCP/IP client connection to an embedded device with a very minimal TCP/IP stack. A bug in
the embedded server device's stack seems to inject some of the QNX TCP options data into the data section of the first
syn-ack frame in the three way TCP setup sequence. When this happens, the QNX TCP/IP stack seems to silently drop the
frame and the setup never completes.
>
> The same connection sequence, with a Linux box as the client, is successful.
>
> Attached is a tcpdump, which can be viewed in Wireshark, that shows the detail. Please see the funny data payload in
frame #2. It's weird, but not technically wrong, I think, and should not have been dropped.
>
> 192.168.1.2 is the client making the connection
> 192.168.1.1 is the server receiving it.
Check the output from 'netstat -pip' and 'netstat -ptcp'
on the qnx end. There should be some stat incremented
when the packet is dropped.
Regards,
-seanb
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