Just another question: Do I need PHP-Suhosin if I have mod_security already installed on my dedicated server? And what is the difference between Apache-Suexec and suphp or php-suexec, make sense to have both installed and in use? Because I have some strange problems with my website, sometimes my site is unreachable for me but if I disconnect and re-connect(change IP) the site is on. There is no server load issues or etc. I had been banned but I dont know who banned me, if mod_sec or apf or suhosin or any other tool.
uEXEC is an Apache module let users to run CGI/SSI programs under user IDs. It is good to track logs to find security problems.
Suhosin is a good guard for php to protect your website or webserver against attacks like sql-injection or remote-file-injection etc.
ModSecurity™ is a firewall-like apache module which protects your webserver against known and some unknown attacks like brute-force data-inclusion etc
suphp or phpsuexec is similar to suexec, let scripts run with user rights also not as nobody. Good to monitor user actions on a webhosting to find spammers etc... Attention!: do not forget to configure your httpd.conf to add suPHP_AddHandler directive, otherwise your php scripts wont work.