[BlueOnyx:25626] Re: Mail server problem with Outlook

[Michael Stauber]

Hi Ken,

> On a server that just does email, there's no reason that a username can't be pretty much whatever you want, @ is just another character.

All authentication services on an RHEL box (and clones) use PAM 
(Pluggable Authentication Mechanism). Which ties into the user and 
password authentication mechanism (/etc/passwd, /etc/shadow).

And /etc/passwd has usernames, not email addresses.

The email addresses are stored in the MTA (Postfix, Sendmail, whatever) 
configuration files and there you actually have a mapping, where the 
email addresses are mapped to individual Linux usernames.

That way: When email comes in, the MTA has a way to do lookups to see 
which Linux user the email is supposed to go to.

So allowing the email address as authorization token (instead of the 
Linux username) is an added layer of unnecessary complexity. Because now 
we can't just ask PAM directly, but have to query the MTA for the Linux 
username and then stuff that into PAM.

So sure, it can be done. But it makes nothing easier or better or more 
secure. /shrug

-- 
With best regards

Michael Stauber