Question: ```
local_machine:$> ssh myself@external_machine_ip_address -p specific_port -X
external_machine:$> echo $DISPLAY
localhost:10.0
external_machine:$> emacs
Warning: Cannot convert string "-*-courier-medium-r-*-*-*-120-*-*-*-*-iso8859-*" to type FontStruct
Warning: Cannot convert string "-*-helvetica-medium-r-*--*-120-*-*-*-*-iso8859-1" to type FontStruct

```

I do see the emacs window, but I can't see any of the characters. What could be the error ?

Answer: 
Exchange is using the same kind of authentication/authorisation as, for example, file shares.

When you connect with an appropriately configured transport (Named Pipes are the simplest) then your authentication information is carried across. In a domain (required for Exchange) this uses Active Directory's Kerberos derived system that means you password (or a hash of your password) is not sent, but rather a token that AD gives you computer. The Exchange server then checks that token with an AD to verify you identity.

See [Kerberos](http://en.wikipedia.org/wiki/Kerberos_%28protocol%29) for more information.

(NTLM also provides SSO in a similar way, but it has some security problems and has been replaced by Kerberos in most places.)
Are you sure you didn't enter your password initially when first setting up Outlook? I believe that as standard it just remembers this.

You can (if wanted) get it to ask your password every time via tools > email accounts > add or modify an existing account > change > more settings > security > "always prompt for username and password"