I would like to see this archived here. This is still absolutely the best free personal firewall there is. Since Kerio has released Version 4 (which is not nearly as good) they have buried the download for 2.1.5 in a server directory that's impossible to find unless you know the URL.
The only time Kerio even mentions 2.1.5 on their site is in reference to "upgrading."
Who knows when they will take it down completely? This great program needs to be saved, and oldversion.com is the place for it.
Here's the URL:
http://www.kerio.com/dwn/kpf/kerio-pf-2.1.5-en-win.exe