Ok, I know this question is going to sound VERY stupid, so sorry, but bear with me as I am a newbie. Here goes:

I understand updating Apache, PHP, keeping all the actual software up to date, etc.

Is there a major risk in not recompiling the latest kernel and installing it?

Example, I'm currently using the stock kernel in CentOS 4.3. I ran yum update and yum update kernel and I believe it patched it.

Is there anything more I need to do?

Where do the major risks of not updating the kernel all the time apply?

Thanks,
Dan

Allowing your distro to keep your kernel up to date is fine 99.9% of the time.

An older kernel (say anything more than a 18 months) usually has some documented flaws. If you patch the kernel around those flaws, running even ancient kernels isn't a problem. New kernels are better for new hardware, but when you have a working system, particularly on a server, there really is no need to upgrade the kernel.

Peace,
JimBass

Also, you do need to rebbot into the new kernel for the upgrade to take effect (this is generally not true for other components, except maybe glibc -- everything else you can usually just restart the affected application(s)).

Thank you very much for your answers both of you, JimBass and btmiller, cleared up everything.