Simplest way to deny access to a class C

[Jorge Biquez]

Hello all.

I am sorry in advance if this question sounds too stupid.

I have a small server for personal use of webpages running:

7.3-PRERELEASE FreeBSD 7.3-PRERELEASE #0

it is working fine , no problem very stable.

I just need to block some IP class C address that are always trying 
to "discover" directories or applications under the web server. They 
do not do and can not do anything since this server has nothing 
installed but i am tired of seeing in the logs all the intents they 
do every 2-3 seconds.

I have not installed any kind of firewall yet.
What do you think is the best way to accomplish this task? If 
possible the easiest one. I do not want to do anything else but just 
bloc IP's, at this moment at least.

Thanks in advance.

Jorge Biquez