[tproxy] connection go to CLOSE_WAIT after sending FIN

Jan Engelhardt jengelh at linux01.gwdg.de
Mon Dec 11 18:27:54 CET 2006

>  This symptom is probably caused by the TCP window tracking patch 
>included in newer TProxy tarballs. (Ie. a new TCP connection tracking 
>engine with a revamped state machine.) So it has nothing to do directly 
>with tproxy, you'd have the same experience without transparent proxying 
>on recent 2.6 kernels.

Window tracking? What does _that_ do? And when exactly is it active
(when tproxy.ko is loaded, or always?)

>  However, I do not think it is a bug. After sending the FIN and receiving 
>an ACK you have a half-open connection, where you're waiting for the 
>other end to close the (now half-duplex) pipe. If you simply close the 

unidirectional (socket). "half-duplex" is word tainted by network
electronics and can mean bidirectional communication over a
(unidirectional-at-a-time) pipe.


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