Before proceeding with the following steps, please make a backup of /etc/postfix/main.cf and /etc/postfix/sasl.
This is the SMTP-AUTH clear text method:
In /etc/postfix/main.cf, make sure you have the following:
smtp_sasl_password_maps = hash:/etc/postfix/sasl
You now need to edit the Postfix "/etc/postfix/sasl" file and hash it. The format of the sasl file is:
The host portion above must match what you used in the "relayhost" line in main.cf. Something as follows:
smtp.ameritech.yahoo.com myid:mypw (your userid and password)
Save the file.
Hash the file.
[email@example.com] postmap sasl
[firstname.lastname@example.org] /etc/init.d/postfix restart
Once you restart Postfix, send a test message through it, and you should see a line in /var/log/mail log similar to:
>, relay=smtp.ameritech.yahoo.com[18.104.22.168], delay=1, status=sent (250 ok 1234567891 qp 12345)