[mkk]

This is a little utility program that is able to increase the limit for simultaneous half open connections that has existed in the Windows world since SP2 for WinXP. I have been testing it for a while with Vista x64 and now with version 2.5 consider it to be good enough to recommend to you guys. As you may already know it has been especially difficult to accomplish this with 64bit Vista due to the forced digital certification check. I have not tried this with WinXP but for what I've read it works fine and it's really 64bit Vista that has proven to be difficult to patch anyway.

I would still not recommend this to users who have yet to experience an actual problem with the simultaneous half open connections limit, since this method involves modifying the networking critical driver file tcpip.sys. It is wise to create a fresh system restore point before trying anything like this out.

Windows Half-open limit fix (patch) - Home

[Judas]

just to clarify..

what is the purpose of this patch.... an example of where it would be a benefit ... or more then one example...

[mkk]

A short description i stole from the web, because I'm to lazy to write myself:

"Windows XP SP2 limits half-open connections (SYN) to a maximum of 10 (the previous limit was over 65,000). This is supposed to slow down certain viruses because their spreading strategy is to try to connect to a high amount of random IP numbers.

The drawback with this connection limit is that other legitimate network intensive applications can be slowed down as well. Applications like security network scanners, peer-to-peer (P2P) applications or a combination of network applications that a power user may be using (VPN, FTP, p2p, RDP, SSH, "Firefox on steroids" and more)."

Edit: I corrected the second passage in my original post. I meant to say that I do not recommend this to just anyone, as not everyone is likely to encounter the limit much or experience it as a problem when they do.

[Judas]

in my case. P2P would be the major benefit

[e v o]

mkk,

I've been looking for something like this for a while. I'm getting an error though.

"There is no access to tcpip.sys. Maybe program started without administrator rights. Visit half-open.com to download a new version or to report about error."

I've tried running as admin and restarting. Any thoughts?

[mkk]

I just tried the latest version (2.6) here and didn't have a problem, but then I always have UAC turned off. I'd suggest testing with either turning off User Account Control temporarily(setting in user Control Panel - User Accounts), or in case your current user account name contains unusual characters create a new one with a simple name to test again. The file tcpip.sys is by default locked down to prevent modification but this tool is normally able to lift that limitation temporarily to do its thing. It failing to do so could be related to the user account so try perhaps making a new account in either case, just for this patching run.

If nothing of the above helps, mail the author with a description of the problem and of the system (Vista SP1 installed or not, and such). He's usually quick to reply.

[e v o]

I was able to do it by creating a new account and doing it from there. I always have UAC off as well. Not sure why it wasn't working off the bat. Thanks for the help and pointing this out.