[CLUE-Tech] SMTP authentication

[Angelo Bertolli]

I'm trying to figure out how SMTP authentication works.  I am using it 
on a server, and I'm just wondering why spammers aren't able to get 
through and relay.

 From ethereal it seems to me that all you do is:
1) send EHLO
2) send AUTH

But AUTH doesn't seem to contain anything about that particular user, so 
what's being checked for authentication?  For example, for me it was 
something like AUTH PLAIN FSJ823ajsa2... but I never sent a userid or 
anything.  I tried to use the exact same line via telnet and I got denied.

Does anyone know how SMTP authentication works?


Angelo