Verify IMAP/POP3 connection to Microsoft Exchange Server 5.5

Question

I wanted to fully explore IMAP connections from the command line, if I can connect via Thunderbird, then I should be able to via telnet?!

Microsoft detail IMAP login as :-

LOGIN NTDOMAIN/NTACCOUNT/ALIAS PASSWORD

The settings in my Thunderbird are :-

<domain>\<username>\<alias>

Various sources state slightly different IMAP commands :-

LOGIN [email protected] <password>                                   (1)
LOGIN <Domain_Name>/<Log_On_Name> <Password>                       (2)
LOGIN <LogOnName>@<DomainName>.<Top-Level_Domain_Name> <Password>  (3)
LOGIN DOMAIN/USERNAME/MAILBOX                                      (4)
LOGIN NTDOMAIN/NTACCOUNT/ALIAS PASSWORD                            (5)

POP attempts :-

telnet <servername> pop3
+OK Microsoft Exchange POP3 server version 5.5.2658.25 ready
user <username>
+OK
pass <password>
-ERR Logon failure: unknown user name or bad password.

user <domain>\<username>
+OK
pass <password>
-ERR There is no such mailbox on this server

The later shows that it my account access was authorised.

IMAP attempts :-

telnet <servername> imap
* OK Microsoft Exchange IMAP4rev1 server version 5.5.2658.25 (<servername>) ready
login <domain>/<username> <password>
login BAD Protocol Error: "Unidentifiable command specified"
login <username>@<domain>.<servername> <password>
login BAD Protocol Error: "Unidentifiable command specified"
login <domain>/<username>/IanVaughan
login BAD Protocol Error: "Unidentifiable command specified"
LOGIN
* BAD Protocol Error: "Tag not found in command"
login
login BAD Protocol Error: "No space following tag in IMAP command"
LOGIN <domain>/<username> <password>
LOGIN BAD Protocol Error: "Unidentifiable command specified"
LOGIN <username>@<domain> <password>
LOGIN BAD Protocol Error: "Unidentifiable command specified"

Solution

You've misunderstood IMAP. Every IMAP command has to be preceded with an identification token, so instead of LOGIN domain/user/mailbox password the KB article you quoted advises you to use ? LOGIN domain/user/mailbox password (note the ? prepended to the LOGIN command - which is the mentioned token).

BTW: you do not necessarily have to use domain/user/mailbox - simply using "user" (the Windows NT logon user name) will connect you to that user's mailbox automatically.

Another thing is the authentication mechanism - plain authentication (simply supplying the password in clear) is discouraged due to its insecurity and thus most servers refuse plain authentication and force users to use a digest auth instead if SSL is not used. I do not know if Exchange 5.5 does so by default, though.