Essential Software: 10 simultaneous connections limit

With Windows XP (SP2) and Vista, there is a limitation imposed by Microsoft on the number of concurrent connections that can be established using TCP/IP to 10 or 25.  This is for security reasons.
While that is a good thing, it impacts heavily on the performance of multi-threaded Internet applications, such as proxy scanning software like Charon.

Users may be familiar with:
“Event ID 4226: TCP/IP has reached the security limit imposed on the number of concurrent TCP connect attempts

The tcpip.sys file is the culprit here and requires either patching or a utility to bypass this problem.


For a newer, easier way around manually modifying the system file, TCP-Z is the tool for the job.



TCP-Z has an intuitive interface
This tool modifies TCPIP.sys in memory and requires no restart.
TCP-Z can be used manually or installed as a virtual device to run in the background and automatically increase the connection count.
Real-time monitoring of DL/ULrates, number of connections and half open connections.

Supports: Windows XP (SP2 or SP3), 2003, 2008, Vista (SP1 or SP2), Windows 7, All 32bit(x86), 64bit(x64)

Version at time of writing: V2.4.0.46, Build 20090108.

Here is the URL:

Note:  At the time of writing, the developer was also working on a patch, because some people have trouble using this program with their AV software and also, there are people who prefer a patch over a utility.


One Response to “Essential Software: 10 simultaneous connections limit”

  1. […] Windows users « Essential Software: The yeah, yeah.. heard it all before index. Essential Software: 10 simultaneous connections limit […]

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: