We applied a series of errata fixes to our server Tuesday. Along with the bug fixes and such, the mail server picked up SSL capability as an unintended bonus. Problem is that since we haven't forked over the cash to buy an official key from Verisign some mail clients are not wanting to trust our mail server anymore. The solution is to either figure out how to make your client accept our unsigned security credentials as is or switch off SSL (sometimes also referred to as TLS) in your mail client's settings.
Our new signup kit (thankfully) defaults to SSL being switched off so should be unaffected.
Outlook/Outlook Express defaults to SSL only so anyone using our system already had to manually switch it off, and therefore should also be unaffected.
With Eudora, go to Tools/Options/Checking Mail and look for SSL. Turning it off will revert to the behaviour prior to our mods.
PINE, if run from a shell on Odin is unaffected. If connecting remote you might (depends on the version) need to change the config. Thankfully it will allow you to connect, it just gives a warning about being unable to verify the signature on our SSL key. It also helpfully provides info on the same screen about supressing the warning message.
While I haven't found an easy way to stop the current pop/imap server from doing SSL, probably a good thing (enhancing privacy is usually a good thing) in the long run anyway so we probably will be leaving it enabled. Hopefully the transition bumps will be minor.
While on the subject of secure things, we now offer OpenSSH on Odin. We have had Telnet blocked from outside access for a few years now, but SSH (Secure SHell) is secure enough to leave open. So if you have accounts with other dialup providers or need to access your shell account here from a work computer, you now have an option. Several SSH clients are freely available for Windows, Mac OSX includes an SSH client and most current Linux distributions include OpenSSH.