without external hardware, DDOS attacks are just a bummer.. well, they're a bummer, regardless
you can install a firewall + brute force protection (software), but that just stops things before they hit httpd.. it IS a good thing to have however..
i highly recommend CSF
Linky Poo (basically a wrapper around IPTables)
after install, it integrates nicely with cPanel/WHM as well... they even offer to harden your box for $100, which is good, if you're a Linux n00b..
BUT, if you like to tinker and know Linux, it's a FREE dealio. easy install and configure.. i've done this on a couple of boxes now and love it..
