Firewall, blocking POP3

[Jorge Biquez]

Hello all.

I am sorry if the question is too basic.

I have a personal small machine running

	FreeBSD 7.3-PRERELEASE #0:

It runs as my web and email server for a cuple of domains. NO clients 
no other users have access to it.

Is there any , easy/faster way to stop POP3 from being working. I am 
running qpopper to be able to download emailes.
I decided to use sendmail since only a few accounts are there and I 
do not need more but in the last days the server has been under a big 
attack where people is trying to guess users and passwords. I am 
using a strong schema of passwords so no problem on that but I rather 
to be sure .

I was thinking on the following options.

- Stopping the service, port 110 to respond and open it everytime I 
want to download email.
- Install a firewall and block all the IP's but they are trying from 
a lot different ones.
- Maybe changing the port for pop3 and change all my devices to use 
another port?

In case I need to start from zero and install a newer version I can 
do it, no problem at all but I am not sure if that helps to do things 
a easier way.
Maybe install a complete different schema of sending receiving email 
(perhaps do not use sendmail to send , change to postfix and use IMAP 
instead of pop3. Would that help?

Thank in advance for all your comments and help.

Jorge Biquez