2009-03-28

telnet - using telnet to test email server or read email (pop port 110) using telnet

telnet has a lot of weakness compare to ssh. Most notably would be it transmits in plain text across the network, which everyone can look at it as long as one can tap into the line.  Still, it is very much useful in trouble shooting application layer problems, e.g. http, smtp, pop, ftp, irc & others.

This post attempt to demonstrate how to use telnet to trouble shoot pop3 protocol problems. Or even better, use telnet to read email on port 110.

Scenario 1 :
Often, when email client such as thunderbird, apple mail, opera mail & others, fails for some reason and its error message indicate that error occurs during communication with the server. But calling the server hosting administrator and they claim that the server is working fine.


Scenario 2:
The machine that we used does not belongs to us. Setting up an email account on it would certainly post security issue to our email account. But then, we just wanna find out what email messages have inside our mailbox. Probably, just wanna read a few lines of the mail message.


Sample of using telnet to check email:
telnet domain.com 110

user username

pass password

At this stage, your email account should be properly authenticate in order to perform the below operation on your email box :
- list (list messages)
- stat (show the total number and size of all messages)
- retr n (where n is the number of the message to read)
- dele n (where n is the number of message to delete, commit only after quite is issue)
- top n (where n is the number of message to list the hearder)
- rset n (where n is the number of the message to undelete, before the command quit is issue)


Use :
quit
to exit from the session.

Hasta la vista !!!

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