If you are sending emails from a website with code, you do not need to specify a remote SMTP server.

Each web server includes a local SMTP proxy server running at the default port (TCP 25), and you can use 'localhost' as the SMTP server.

If you are using CDO or w3JMail, you do not need to specify a remote SMTP Server, as they use 'localhost' by default. ASPEmail requires that you specify remote server address anyway, and you should use 'localhost' for this setting.

For ASP.NET, use 'localhost' as the host name

No authentication (User name and Password) is necessary to send SMTP mails with code.