For various reasons I have a requirement to have an app listening on localhost which is proxying output from another app that is not under my control. Currently the OS is buffering too much data (I think >XP the OS buffers >64KB ish?) and I need to try and find a way to crank down the OS buffers without making a system wide registry change

The solution appeared to be to use the TCP_MAXSEG option:
  setsockopt($server, &Socket::IPPROTO_TCP, &Socket::TCP_MAXSEG, 2048);

However, on activestate at least this is giving me:
  Your vendor has not defined Socket macro TCP_MAXSEG, used at xxx

Any ideas on how I can control OS buffering on Win32? (I need it portable eventually, but win32 is my problem right now)

I believe that the trick on windows is to set the advertised MSS window (as above) and this then changes the window size that the sender uses

Right now I can use SO_RCVBUF on the receiving side to turn down the receive buffer, but I am still having problems with the sending buffer (which is outside my control) being way too large for my requirements

Any help please?

In reply to Control TCP_MAXSEG (OS buffering) on Win32 by TheWildgoose

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