No more TCP connection attempts limitations

Apr 10, 2007 14:11 GMT  ·  By

Are you a hard-core peer-to-peer user? Then you are already aware of the limitations that Windows XP features when it comes to incomplete TCP connections. What you might not know is the fact that those restrictions have transitioned into Windows Vista. The maximum level of the simultaneous incomplete outbound TCP connection attempts per second in Windows Vista is associated with the editions of the operating system.

The Windows XP SP2 and Vista TCP connection attempts limitations are focused on improving security, but an immediate downside is the fact that it impacts BitTorrent applications. Heavy users of P-2-P networks will find that their transfers will be slowed down. Fortunately, there is a workaround.

However, and this will also act as a disclaimer, while I will provide you with a tutorial to bypass the TCP limitations and also point you in the direction of two patches, I advise you to exercise caution when performing the process. Otherwise, neither I nor Softpedia are responsible of the way you choose to use P-2-P networks and applications.

Right, with this out of the way, you will first of all need to download the patched tcpip.sys: 64-bit tcpip.sys or 32-bit tcpip.sys. Then simply launch command prompt and enter the commands below:

takeown /f c:windowssystem32drivers cpip.sys cacls c:windowssystem32drivers cpip.sys /G "username":F

Make sure that you replace "username" with the actual username you use for logon. In the command prompt you will have to enter: netsh int tcp set global autotuninglevel=disable in order to turn off the TCP/IP auto-tunning capabilities.

The bcdedit.exe -set loadoptions DDISABLE_INTEGRITY_CHECKS command is a must for 64-bit Windows Vista editions. X64 Vista features integrity checks, meaning that drivers need to present legitimate signatures.

Next you will have to make your way to the C:windowssystem32drivers folder and replace the tcpip.sys with the patched file that you downloaded in the beginning. Navigate via regedit to HKEY_LOCALL_MACHINE > SYSTEM > CurrentControlSet > Services > Tcpip > Parameters registry key. Here simply enter TcpNumConnections as a new "DWORD value." All you are left to do now is to double click TcpNumConnections and set whatever value you wish, also setting the maximum limit of TCP/IP connections. Make sure to restart you machine.