(Posting in an old thread coz this is all I could find on TE)

I'm using Vista Ultimate x64, getting the 4226 event so searched and found a couple of links (other than the above):

64-bit (x64) Windows Vista SP1 (6001.1800) tcpip.sys Auto Patcher to Fix Event ID 4226 and Unlock Increase Maximum Connections Allowed Tip and Trick

Windows Half-open limit fix (patch) - Home

I know Vista has some driver signing etc and looking at the half-open download there is a "test certificate" with all sorts of permissions which looks like danger to me...

Anyone tried these out and/or know if there are any problems or should I go ahead and install? AVG antivirus doesnt give any warnings...