Having SMTP Authentication in place on your mail server has a number of benefits. SMTP Authentication can add another layer of security to sendmail, and has the benefit of giving mobile users who switch hosts the ability to use the same mail server without the need to reconfigure their mail client settings each time.

How To Enable SMTP Authentication

We found few client still does not enable the STMP Authentication on their email setting on Outlook Express or Microsoft Outlook, in that case some of client sometime facing difficulty to send out email, please follow below instruction on how to enable STMP Authentication on your Email Application:

Outlook Express or Outlook 98/2000

- From the Tools menu select Accounts. The Internet Accounts box appears.
- Select the Mail tab. Your email account appears, usually labeled mail.yourdomainname.com
- Click on the account mail.yourdomainname.com and click the Properties button on the right. The mail.yourdomainname.com properties appear.
- Select the Servers tab. Under the Outgoing Mail Server section check the box My server requires authentication and click the Settings.. button.
- The Outgoing Mail Server box appears. Click the Use same settings as my incoming mail server
- Click OK to close the Outgoing Mail server box.  Click OK to close the mail.yourdomainname.com  Properties box.  Click the Close button to close the Internet Accounts box.

SMTP authentication has now been enabled.

Microsoft Outlook

- From the Tools menu, select Email Accounts. The Email Accounts box appears.
- Verify that the circle-box View or change existing email accounts is selected and click Next.
- Your email account appears, usually labeled mail.yourdomainname.com
- Click on your email account, usually labeled mail.yourdomainname.com, and click the Change button on the right. The Internet Email Settings appear.
- Click the button More Settings... in the lower right-hand corner. The Internet Email Settings box appears.
- Click the Outgoing Server tab.
- Click the circle-box My outgoing server (SMTP) requires authentication, and verify that the circle-box Use same settings as my incoming mail server is selected.
- Click OK to close the Internet Email Settings box.
- Click the Finish button to close the Email Accounts box.

SMTP authentication has now been enabled.