At my company we've had a longstanding problem of not being able to send email from devices outside of our internal network and any specific IP address that we open the relay to. As it turns out, SASL has never been set up. I need to set up SASL ASAP but none of the guides I've found seem to work.
This is the latest guide I tried:
HowTo/PostfixAndDovecotSASL - Dovecot Wiki
I did everything on here minus the last part because it's on the same server.

Also, instead of
submission inet n - - - - smtpd
I did: inet n - - - - smtpd

After all is done, however, I'm unable to send any mail. Thunderbird just says sending message but doesn't send and I don't even get an error. I end up having to disable SASL again before I can send mail.

Dovecot version 2.0.9
Postfix version 2.6.6
CentOS 6
I have Postfix, Dovecot, and ASSP on the same server.

Thanks everyone.