How do I secure my email server

Every day I get a message like this:

Quote:

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--------------------- sendmail Begin ------------------------
Relaying denied:
From [211.206.189.140] to infobank7655@hanmail.net: 1 Times(s)

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The IP and email address may change but there always seems to be someone probing my system.
I also get:

Quote:

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--------------------- Connections (secure-log) Begin ------------------
Connections:
Service pop3:
198.64.140.152: 1 Time(s)

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The IP address is not one of mine. I don't know what they are doing but I can't imagine they mean me any good.
Question #1: How can I be sure that there is no unauthorized access to my mail server?
Question #2: How do I set up my email server so that it requires Secure Password Authentication (SPA) in Outlook?
I don't consider myself overly paranoid, but everyday since I have got my static IP address someone has been touching my system.

what POP3 Daemon are you running?

You are bound to see hundreds of connection attempts, as spammers scan entire Class A IP ranges at a time looking for badly configured mail servers that will relay their spam.

Really your POP server should be IP restricted if its just for home access, and unless you have a domain that you have set MX records on to point to your mail server, you should proberly ip restrict(firewall off) SMTP as well.

Jason

I am running RedHat 9.
I have set up the IP restrictions but I do not know if that will block me from accessing mail when I am not at home.
I do not like the idea of sending the user name and password to the mail server in clear text because it is the Linux user name and password as well.

What settings do I use in TRUST_AUTH_MECH and confAUTH_MECHANISMS to get Outlook to use SPA?