TCP-Z is probably the best tool available to crack and patch Windows’ tcpip.sys, which responsible for TCP/IP network connectivity and notoriously, half-open TCP connections limit. TCP-Z works by patching the value of half-open outgoing TCP connections limit in kernel memory instead of physical tcpip.sys file itself, which requires Universal Tcpip.sys Patcher. Introduction to TCP-Z is available.

The author of TCP-Z has updated TCP-Z for one last time to version build 2009.04.09, as starting from Windows Vista SP2 and Windows 7, Microsoft has removed the half-open outbound TCP connections allowed limit.

For user who may still believe that the Windows OS may restrict or limit the rate of number actual connections that are been created, or still seeing event ID 4226 been logged in the Event Viewer, or still using Windows XP or Windows Vista RTM/SP1, it’s still possible to download and use the newest version of TCP-Z to view the TCP/IP connection details and/or patch the half-open TCP connections limit value if required.

Download TCP-Z 2009.04.09 V2.6.2.75

Download Link 1: tcpz_20090409.7z (7Z File, 438 KB)
Download Link 2: tcpz_20090409.7z (7Z File, 438 KB)

TCP-Z version has increased range of searcher to make it support wider range of operating system, including future release. As such, it supports all version of Windows XP, Windows Vista and Windows 7, both 32-bit (x86) and 64-bit (x64) inclusive.

Note that since TCP-Z version 2.6, the Virtual Drive (driver to load TCP-Z on system startup) no longer available. To automatically patch kernel memory with another higher limit of TCP half-open connections, use one of the following command to autorun on system boot up or download the old version of V2.5.

tcpz.exe -limit:200
tcpz.exe -limit:200 -autoexit

Download Link 1:
Download Link 2:

Note: Since Windows Vista and Windows Server 2008 SP2, there is no more restriction (now unlimited) concurrent half open TCP/IP connection limit, although the limit remains active at Windows XP.