I recommend not having smtp listening on port 25 on your web server
unless it is really acting as your mail server. Outgoing messages
from your web server can be handled without it. You may have to set
up a cron job to clear your outgoing mail queue but I prefer that to
having another potential security problem.
I also recommend, if you are running ssh on your web server, that
you tell it so listen on some 5 digit port (using
/etc/ssh/sshd_config on my system, may vary on yours). There is no
need to run ssh on the standard port as only people knowledgeable to
your setup ever have need to connect to it. (Unless you're hosting
shell accounts or something neat like that.)
