Since my earlier post, I pulled up Yast software management. I see that “qpopper” is available in the standard repos. It’s a pretty simple POP3 server. It logs the IP address and the user who logged in. It runs via inetd/xinetd. It supports APOP, but you would need a separate database entry for APOP. The separate database entry is good. You could setup user accounts with no login possible, and only APOP auth for POP3.
My guess is that Yast will do most of the setup for you - as mentioned, qpopper is simple. You would have to setup port forwarding on your router for POP3 (usually port 110). According to software management (the “dependencies tab”, the qpopper package also provides “config (qpopper)” which is probably the Yast stuff for setting it up.
Here are qpopper log entries from an old, about to be retired, solaris box at work:
Dec 30 11:02:09 mp popper[6389]: (v4.0.8) Servicing request from "209.85.223.999" at 209.85.223.999
Dec 30 11:02:09 mp popper[6389]: Stats: userid 0 0 0 0 209.85.223.999 209.85.223.999
I don’t have any APOP users who still access that box - the only users are people who have not heard that the box is about to be taken down. But the log for APOP entries is similar.
I did munge that data (hid the user login name, and changed the last 3 digits of the IP address) to ‘999’.
And “fetchmail” is in the repos - I standardly install that, and use it for checking a few mail boxes. I just use from the command line. Setting up user crontab entries to do that should be easy enough. As I recall, the man pages for fetchmail are a bit turgid, but you can probably find online help with a google search.
It should work interactively, but not from cron if it requires a passphrase to be entered. Maybe there’s a way of using an “expect” script to feed it a passphrase.
If it doesn’t work interactively, then use “ssh -v -v -l user ip-or-hostname” to get verbose information on what is happening.
I personally run ssh-agent for handling key stuff, so I haven’t tried it directly with the standard keyname that you are using. I suppose that I should one day experiment with that.