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Re: Mixed up protocol packets in server response?

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transaction. No passing connections by hand anywhere, everything should be
nicely thread-bound. Still, if not here, where could it go wrong?

I have seen two cases in my career where there was an "evil box" on the network that corrupted the traffic. The first was a very long time ago (in the late '80s) but the second was only a couple of years ago and presented with very similar symptoms to your report. This happened at a consulting client's site (actually between two sites). Weird "franken-packets" showed up once in a while, leading to a protocol decode failure. Luckily we had been involved in writing both the client and the server, and therefore had a high degree of confidence that they were correct. The network administrators denied strongly that they had any equipment deployed that touched the payload of any packet. They denied this several times. Eventually we were able to take packet traces on both client and server machines, correlate the traffic (not necessarily an easy task), and prove conclusively that what had been sent from one end did not show up intact at the other end. A few days later the network people revealed that they had some sort of firewall/traffic management box
that was mangling the traffic.

Having said that, bugs in buffer management code are also not uncommon, and can manifest intermittently since they may be triggered by specific boundary conditions, specific received data buffer size, and so on.

I have also seen once case of data leaking between threads in an unpleasant and intermittent way in a Java application, in buffer management code that attempted to avoid GC overhead by re-using
buffers across sessions. So that's definitely a non-zero possibility too.



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