I found an easy way to test a pop3 connection today. It is a little know tool called telnet (It’s not really little know, but I never though of using it for pop3 so in my mind it is little known for that purpose).
From a command line in windows:
telnet NameOfPop3Server 110
user username
pass password
list
You will see a list of email in your mailbox
retr msgNumber
You will see the email you requested
quit
More POP3 commands:
stat – Returns the number of messages in mailbox and size of mailbox
dele msgNumber – Marks message msgNumber for deletion.
noop – Doesn’t do anything, just returns a positive response.
rset – Unmarks any messages that are marked for deletion.
top msgNumber numLines – Returns the header info and numLines of the body of message msgNumber.
uidl msgNumber – Returns the message number and the messages Unique ID Listing.
Note: If the telnet session ends for any reason other than using the quit command, messages marked for deletion will not be deleted.