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I have the exactly same problem as here: Windows XP TCP/IP No buffer space available

On Windows XP Pro, SP3 if one does an experiment where one tries to open TCP/IP sockets in a loop (bascially, listen port 7000, listen port 7001, etc.)

After approx 649 open sockets, one will start getting errors: No buffer space available (maximum connections reached?)

I've tried to edit the registry as described here I set MaxUserPort = 65534 and MaxFreeTcbs = 2000, but it didn't help.

What else can I do? I need 1000 server sockets.

Here is the error stack:

05.04.2012 10:23:57 No buffer space available (maximum connections reached?): listen at Method) at at at at channelserver.NIOAppServer.initSelector( at channelserver.NIOAppServer.( at channelserver.NIOServer.main( at channelserver.NIOServer.main(

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Googling for the error, everything seems to refer to Java/JDBC. Is this a Java app you're writing? If so you may get a better response over at Stackoverflow. – Chris McKeown Apr 5 '12 at 7:34
Yes, this is Java application, but there is nothing about jdbc in error stack. Anyway, thanks for you help, I'll try to ask there – Natalia Apr 5 '12 at 8:00
Check this out too:… – Chris McKeown Apr 5 '12 at 8:20
I've seen this, but found nothing suitable. – Natalia Apr 5 '12 at 8:30
up vote 0 down vote accepted

Just in case someone would face this problem too.
Finally it seemed to me that it's just WinXP's problem. I've tried the same code with more RAM - results were the same. But when I've tried it on Win7, everything worked fine even with 1200 sockets.
So, WinXP is just not suitable for such tasks.

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