Half-open limit fix (patch) for Windows

Half-open limit fix is a program designed to change the maximum number of concurrent half-open outbound TCP connections (connection attempts) in the Windows system tcpip.sys file.

Microsoft first introduced this limit in Windows XP SP2 and it is present in later versions, which purpose is to try to slow the spread of virus and malware from system to system, and also to reduce the impact of infected systems participating in DoS (Denial of Service) attacks.

Microsoft's limiter makes it impossible for Windows systems to have more than 10 concurrent half-open outbound connections; after 10, new connection attempts are put in a queue and forced to wait. Thus, the speed of connection to other PCs is limited.Therefore, the speed of connection to other computers is actually limited.

P2P (peer-to-peer) programs like µTorrent, BitComet, eMule, P2P TV, etc.,are generally the programs mostly affected. Since bittorrent apps tend to use up all 10 of the half-open connections, other Internet activity—especially the loading of web pages—can become extremely slow. The delay before opening a new page can take over ten seconds: this delay occurs regardless of your Internet connection speed.

Half-open limit fix remedies this problem by increasing the maximum limit of half-open connections. For most Internet users, changing the limit to 100 will be more than sufficient.



Instruction :
1) Run Half-open limit fix
2) Choose a new limit of concurrent half-open outbound connections quantity and press "Add to tcpip.sys" (for most Internet users, changing the limit to 100 will be more than sufficient)
3) Restart computer and enjoy

Running the program again may be required if Windows updates tcpip.sys, such as when a new SP is released. If program ceases to work on an updated tcpip.sys file, a new version will be available at this site.

Vista and Windows 7 users: Perhaps in the future, after updating Windows or installing a new Service Pack, a "Test mode" watermark may appear. It may appear because in all versions of Vista and Windows 7 (except in Vista x86 without SP1) there is the imposing drivers signature check, and the tcpip.sys file sign with test signature after patching. In such case, it should only require a simple re-installation of the program to remove the watermark.


Operating system : Windows XP SP1(x64)/SP2(x86,x64)/SP3, Vista without SP(x86,x64) and with SP1(x86,x64), 7 beta(x86,x64).
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Size: 360KB.