Utilizing SMTP AUTH
Types and Concerns

Choosing what type authentication to use
CRAM-MD5
Challenge Response Authentication Mechanism
Requires plain-text on client/server
But is encrypted in transit
PLAIN
Credentials traverse the network plain-text
But, password can be encrypted on the server
LOGIN, Microsoft SPA are also supported
SASL supported using the Cyrus saslauthd

Concerns
Setup so that PLAIN requires STARTTLS
Plugging into PAM, LDAP, MYSQL etc
Client (MUA) considerations