[BlueOnyx:25623] Re: Mail server problem with Outlook

[Michael Stauber]

Hi Ken,

> What if we host mail for domains foo.com and bar.com, and we have a mail
> account for john at foo.com, what if there is also a john at bar.com.  Sorry,
> there can only be one "john" on the entire server.  So the second john has
> to be john2?


That's what "Email Aliases" are for and every user can have an infinite 
number of them. Linux user names must be unique on the server. Email 
Aliases (at least the part left of the @) can be identical across Vsites.

Examples:

Username / Vsite:	   Email-Alias:
john    (Vsite: site1)	   john at site1.com
john2   (Vsite: site2)     john at site2.com
s3_john (Vsite: site3)	   john at site3.com
[...]		           [...]

There is another benefit: If the email address is also one part of the 
login credentials (and the remaining part being the password), then 
you're already exposing half of the login credentials to the whole 
world. If the login is via the Linux username and you use Email Aliases, 
then you can make that a little less obvious.

I am actually running a Fail2ban config that automatically blocks login 
attempts via Email address on first attempt, because there we already 
know that someone is already on a fishing trip. But your mileage might 
be different, so that's why it's not part of the standard Fail2ban 
config in the shop PKG.

-- 
With best regards

Michael Stauber