POP has no security
$ telnet/port=110 mail.opus1.com
Trying... Connected to MAIL.OPUS1.COM.
+OK cello.Opus1.COM MultiNet POP3 Server Process V4.0(1) at Fri 20-Sep-96 3:21PM-MST
+OK User name (trumbo) ok. Password, please.
+OK 3 messages in folder NEWMAIL (V4.0)
+OK POP3 MultiNet cello.Opus1.COM Server exiting (3 NEWMAIL messages left)
Connection closed by Foreign Host
You can test passwords by connecting to the POP port