Bitcomet Half Open Connections Limits
So, i’ve added this as a seperate edition, as you know, the connections are limited so this guide teaches you how to bypass it 
Windows XP Service Pack 2 (available here) includes an array of new security “enhancements”. One of these so called enhancements limits the number of simultaneous incomplete outbound TCP connection attempts (’half-open connections’) per second to 10. 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. While this limit will slow down viruses, it will also slow P2P (peer-to-peer) applications that establish lots of connections over a short period of time. BitComet is one such application.
When the half-open connection limit is reached, new connections will be queued until some of the current connections are established. The 10 half-open connection limit applies to Windows, not just BitComet, so if BitComet is using all 10 half-open connections and you try to load a page in your web browser it may take a long time to connect, or even time out.
Please don’t get the half-open connection limit confused with BitComet’s “Connections per task” — once connections are established they’re no longer bound by this limit.
How do I tell if I’m reaching the 10 half-open connections limit?
Go to Start > My Computer > Control Panel > Administrative Tools > Event Viewer > System
Click the Event column so it’s sorted by the Event ID and look for 4226, like this:
If you right-click the 4226 warning and select Properties it will show you a brief description of the warning, like this:
I’m getting this warning, so what do I do about it?
If you’ve received a 4226 warning, or want to ensure you won’t get any, you can alter the maximum connection limit using LvlLord’s TCPIP.SYS patcher available from the official website: www.lvllord.de
For vista, try here (by ionstorm)
P2PForums.com download mirrors are available for v2.23d (1st May 2005):
Mirror 1 Adelaide, South Australia (Thanks to Dragosani)
Mirror 2 Adelaide, South Australia (Thanks to D-503)
Mirror 3 Texas, USA (Thanks to Dragosani)
Mirror 4 Texas, USA (Thanks to Dragosani)
What should I change the limit to?
It’s recommended that you set it to 50, then reboot, start up your normal internet programs and check the Event Viewer. If you’re still receiving 4226 warnings, run the patch again and increase the limit by small increments until you are no longer receiving warnings. I run 2-3 different P2P applications along with my web browser and a couple of chat programs all simultaneously so I have set mine to 100.
If you want to change the limit back to default(10), just run the patch again.
NOTE: Some Windows Critical Updates change this limit back to 10 (with no notification), so after installing windows updates you should either check the Event Viewer or run the patch to make sure you’re not limited to 10 again.
So that’s all?
Almost. BitComet has it’s own internal limit, so to ensure BitComet is able to take advantage of the increased amount of connections, you need to enter the same amount in BitComet as your new Windows limit:
Options > Preferences > Advanced > Connection > “Max half-open TCP connections”
If you do a lot of web browsing or use several other internet applications while BitComet is running, try setting BitComet’s limit a little under the maximum you’ve set for Windows (5 or 10)… This will leave a little headroom for other applications.
Technorati Tags: Bitcomet Half Open Connections Limits
April 5th, 2006 at 10:51 pm
Thanks for the info on bitcomet.
Heres a that some might find interesting, is a first person multiplayer shooter called STARSIEGE TRIBES…its maker released it free to the public, here the download site
http://www.fileplanet.com/140246/140000/fileinfo/Starsiege:-Tribes-Full-Game
April 6th, 2006 at 3:12 pm
oh thx for the URl, i’ll try the game out
September 26th, 2006 at 2:27 am
LvlLord’s TCPIP.SYS patcher doesn’t change TCPIP.SY_.
“Windows reinstalled an other TCPIP.SYS version with another limit than choosen.”
Can’t figure out how to get change to stick. TIA for any suggestions.
October 20th, 2006 at 2:21 am
Tried to download the patch via http://www.lvllord.de, however NOD32 seems to think it’s a virus, what’s up with that?
October 20th, 2006 at 8:31 am
No idea since I don’t use it, I use norton instead, my best guess, since lvllord’s patch changes system files, so nod32 thinks it’s a ‘threat’ to the system
December 1st, 2006 at 12:18 am
lvllord’s file is not a virus I have used it for quite sometime on my system it is usually detected as a virus because some viruses require a higher connection and hence change this file thats the reason why lvllord’s file also shows up by a virus.
If you use this file you will notice that it will throw several warnings asking you if you are sure you want to change this setting, I dont think any virus informs you that its operating on the system files.
This is to Ray who commented that it does not change FYI, if you read the documentation after the file is run and you changed the setting windows will throw a window asking you if you want to restore the original file just say ignore to it and the setting will not revert back
April 30th, 2007 at 3:51 am
I made an autopatcher for vista here
http://securevista.blogspot.com/2007/04/vista-tcpip-limit-patch.html
May 28th, 2007 at 12:11 am
thanks, I’ll add the link to the post
August 2nd, 2007 at 8:01 am
Yes all antivirus software said that’s EvID4226Patch is a virus,because he change system files.
Here is another program “xp-AntSpy” http://www.xp-antispy.org.
Install this program,clik on tab Special>Connection Limit,but first go to “Save mode”…choose how much connections and hit patch.That’s it!
I personally put 100 connections,much more is not recommended for system security.
Sorry about my english,greets from Serbia,enjoy!
September 26th, 2007 at 8:51 pm
I’v tried the EvID4226Patch but my connections still don’t work. It says 50 connections..is this OK. How do I set it to more connection..We having problems with this fujacks 32 L worm..how do we clear it
September 27th, 2007 at 10:15 pm
actually, 50 is quite enough, we’re only worried if you’ve installed SP2 and it is now set to 10, then you need to change it,
February 11th, 2008 at 7:38 am
Can you not just change the limit to 50 without downloading some patch???
Is it safe to simply change it from 10 to 50?
April 7th, 2008 at 6:10 am
Thank god that I found this, really helped me out alot!
Finally i’m not limited to 10 ^^
Also thank you Ivan for XP-AntiSpy, worked perfectly.
April 21st, 2008 at 8:36 pm
Thanks a lot
i changed the limit to 100 with 75 for BitComet.
June 6th, 2008 at 3:20 pm
Bitcomet warns that the Half Open limit is too low and suggests you change it in Bitcomet.
I am on XP SP2 and I did this change.
(Fortunately, BitComet keeps a backup of the original TCPIP.sys file).
Then after the change, my PC kept rebooting after a short while, could not track it down for a few days as I had changed the .sys file a few days before and had gone on holiday.
Finally restored the backup and no more rebooting.
So, now I am wary as heck about changing the setting.
If you do so, please makse sure you have a backup of the original somewhere safe.
June 6th, 2008 at 4:23 pm
Thnaks for the tip on XP-Antispy, I downloaded from
http://xp-antispy.org/index.php/home
It does not interfere with your existing anti-virus app but read all the help before changing anything. Changed TCPIP.SYS to 50, hoping all is well.
August 3rd, 2008 at 5:43 am
Hey guys, I tried to run the patch on my system, WinXP SP2 (Spanish) but I gave an error message saying the file couldnt be found, or something.
Is this because my system is in spanish?
Or is it something else?
What can I do if the patch doesnt work?
Thanks a lot.