smtp_sasl_password_maps = hash:/etc/postfix/saslpass
…
# cat /etc/postfix/generic
- /^(.*)@(.*)$/ jdoe@example.com
+ /^jdoe@(.*)$/ jdoe@example.com
+ /^root@(.*)$/ jdoe@example.com
# postmap /etc/postfix/generic
# cat /etc/postfix/saslpass
[127.0.0.1]:12345 jdoe@verizon.net:YOURPASS