well, there are two steps i would take. if those ports are open you may be running those services. port 25 is sendmail, and if you're not running a mail server then you want to prevent it from starting up. all your startup scripts are in /etc/rc.d/ so you should remove remove execute permission like this:
chmod -x /etc/rc.d/rc.sendmail
i believe port 37 (time) is part of identd. you should go into /etc/inetd.conf and comment out lines 22-23 (if my notes are correct) before restarting the service
(and again for inet2 since i don't know which one is affected).
second, i would make sure you have some sort of firewall enabled, and that you set up your policies to drop all incoming packets EXCEPT the ones you need open. a quick search on iptables should give you enough to get started.