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After some time of running fine, one of our Windows XP SP3 machines does not open some(!) new TCP/IP connections anymore.

Putty says Network Error: no buffer space available, IE won't open any new connections but e.g. network drive mappings still work, even new ones can be established.

netstat does not show more open connections that usual, ping and DNS lookups work fine.

Any hints?

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3 Answers

I recently install the kleopatra Outlook GPG plugin which was eating all the resources and due to this I am also getting same error. By removing that plugin everything working smoothly.

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Same experience here. In fact AFTER the error occurs, if you shut down Klepatra, the "no buffer space" error would go away.

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Have seen this issue in the past on Win98. It was resolved by adding a key to the registry "MaxConnections" to override the default buffer size.

Looking for a fix for XP the following may help:


An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full.

Start Registry Editor.

Locate the following subkey in the registry, and then click Parameters:


On the Edit menu, click New, and then add the following registry entry:

Value Name: MaxUserPort

Value Type: DWORD

Value data: 65534

Valid Range: 5000-65534 (decimal)

Default: 0x1388 (5000 decimal)

REF http://smallbusiness.support.microsoft.com/en-gb/kb/196271

Sorry if it doesn't help.

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