CentOS 5 Server - Keeps going offline

[Matty]

Hello,

I have been running my website on a dedicated server for around 3 years now with Fasthosts.

Everything had been running fine until recently and I believe that the server is now being attacked.

I am unsure on how to check why the server is going down, although I have had the server for so long I am still new to Linux and whenever I need to change some sort of setting Google has always been my answer.

So could someone please help me find out what is going wrong and how to rectify it?

I would also like to be able to get it so that if the server itself or any of the services on it could start themselves back up if they where ever to go offline in the future aswell if possible.

Thanks.

[ccolumbu]

You can look into these for security and automatic blocking (there are many others)
snort
fail2ban
pam_abl
rkhunter

As far as re-starting, I rolled my own program for that, but I understand nagios can do it.