SMTP stands for Simple Mail Transport Protocol, the SMTP settings allow you to configure your DotNetNuke website to be able to send email.

SMTP Settings

You can manage the SMTP settings from your hosting provider or network administrator. Configuration of the SMTP settings is done from the Host/Host Settings page.

SMTP Server and Port

This setting is used to provide the server and port information for your SMTP server. If you have an SMTP server running on your local web server you can use the following common settings
localhost
127.0.0.1
If you are connecting to an SMTP Server on another computer/server you would use something like mail.dotnetnukedemo.com (or whatever you have configured for the DNS settings for your mail server.

SMTP Authentication

To secure outgoing mail servers from abuse from spammers often times they will require Authentication to send emails. You can choose which type of authentication based on your server settings and then populate the authentication info if you choose a setting other than Anonymous.

SMTP Enable SSL

If you SMTP requires encryption for sending emails you should enable the SSL settings as well.