I personally would not consider a DOS attack to be hacking. My definition of hacking is compromising a system and stealing information or changing content.
Yes, muman, a good firewall should help prevent these types of attacks but there are possible ways around that which I will not go into here.
As for server updates, they really do need to be applied on a regular basis. Chaim, is the jtf.org server(s) under your direct control or do you depend on the hosting company to apply updates and patches?
Either way, this site is actually in a uniquely advantageous position since it purposely goes offline every Friday evening. It would be the perfect opportunity to apply any outstanding updates. Yes, I know, it would have to be done during Shabbat but maybe you could find a gentile at the hosting company who could do it.