Question

can someone tell me the command line call or file in an ubuntu postfix mail server to find my smtp username and password?

Or do you even need an smtp username and password for your server to send email?

if it is helpful i’m using PHP/Codeigniter which includes the email library described here:
http://codeigniter.com/user_guide/libraries/email.html

Answer 1

Assuming you just want to send the email from php, you could just use default “Internet Site” postfix configuration and you wouldn’t need to set up smtp authentication.

In production, you’d also need to add SPF record to your DNS zone to increase chances of avoiding spam filters.