EventID 4226: TCP/IP has reached the security limit

[NIM]

Windows XP with Service Pack 2 and Windows Vista have both a TCP/IP connection limit that limits the half-open connections of the system. If that limit is reached a new entry in the Event Viewer is created stating “EventID 4226: TCP/IP has reached the security limit imposed on the number of concurrent TCP connect attempts.”. ( I had a bunch of those logs in the event viewer )

Microsoft probably set this limitation to prevent worms and other malicious scripts from spreading to fast or to limit file sharing. Users will most likely notice that something is wrong when running P2P clients, slow downloads and timeouts are indicators that the limit is set. Slow browsing, no matter which browser do you use, is also possible, like it was in my case..

Thankfully a solution exists that can patch the tcpip.sys file and remove the security limit. To do that you need to download the Vista TCP Patch, open an elevated command prompt with administrator rights and enter the following command.

VistaTcpPatch /n X with X being the maximum amount of half-open connections allowed on that system.

The computer needs to be restarted afterwards. Some users reported that they needed to execute Vista TCP Patch from the \Windows\System32\ folder to make it work.

Windows XP users can download and run the software EventID 4226 Patcher Version 2.23d instead which basically does the same thing but sets the limit to 50 half-open connections.

Vista patch: VistaTcpPatch.rar

XP Patch: EvID4226Patch223d_en.zip

In my case, I didn't patched tcpip.sys file, I've just limited number of connections in my uTorrent client.

Global maximum number of connections was set to 200, and I've changed it to 100.

Maximum number of connected peers per torrent was set to 60, and I've changed it to 30.

This action seems to fix my problem I posted here:

http://www.wincert.net/forum/index.php?showtopic=2375

[cygnus]

Thanks for this topic N1k!

On the topic of torrent connections, what I have found best for each torrent is around 15 - 20. Private torrents it's better to have a lower number, but for public torrents with many peers/seeds (ie, Ubuntu downloads) it's better to have a bit more connections. Up to 30 at most as you have it configured. Also, limiting your upload speed to 80% of your maximum upload I find works wonders

Thanks again

[NIM]

Private torrents it's better to have a lower number, but for public torrents with many peers/seeds (ie, Ubuntu downloads) it's better to have a bit more connections.

The problem is that I'm downloading from private sites and from public sites...

I'm open for any testing on this issue :icon_cool:

My current download speed is 8Mbit and upload 512Kb

[MGoodfella]

Windows XP with Service Pack 2 and Windows Vista have both a TCP/IP connection limit that limits the half-open connections of the system. If that limit is reached a new entry in the Event Viewer is created stating

[ricktendo]

I managed to find it but my AV will not let me dl it http://www.4shared.com/file/p59X3hB8/EvID4226Patch223d_en.html