It’s quite simple, really: POP3 (Exchange, dovecot etc) you know, IMAP (Exchange, dovecot, courier etc) you know — so this is just a recap, right? You know how to telnet into the machine — in Vista or Windows 7, you may need to install it separately using “Add/Remove Programs”, or just use Putty in Telnet mode… otherwise, apt-get install telnet if it’s not on your machine (or yum install telnet)
POP3:
telnet SERVER 110 (more…)