CPanel & SMTP Auth

Should work just fine out of the box. Just tell your clients to enable SMTP Auth in their email client. If they are SMTP authenticating with the same username as the POP3 username that they use in their email client, there should not be a problem.

For instance, if your client's email address is bob@domain.com and he has his email client set up to POP mail for bob@domain.com, then typically he'd only need to go into his email client configuration for the bob@domain.com account and enable SMTP Authentication.

Depending on the email client, he may have to specify the credentials to SMTP authenticate with - and if he needs to do that, he would add bob@domain.com as the smtp authentication username, and of course an appropriate password.

Mike