• Basic authentication requires the use of a user name and password.
• If you select Basic, then 25 is the default value in the Port field.
• OAuth uses access tokens to grant authorization without sharing usernames or passwords.
  
  • Use the OAuth method and get client credentials from your authenticating app, like Microsoft or Google.
  • If you select OAuth, 587 is the default value in the Port field. Transport Layer Security (TLS) is the default SMTP Encryption type.
  • Learn more about Using OAuth 2.0 to Access Google APIs.
• Type the DNS address or IP address of the SMTP email server.

• Type the port ID the SMTP email server is using if it isn’t using the default port.
• If you selected Basic as the authentication method, the default port is 25.
• If you selected OAuth, the default port is 587 and the default Encryption is TLS.

Select the type of encryption to use between the SMTP client and SMTP server when sending email.

• Select None to disable encryption; this option typically uses port ID 25.
• Select SSL (sometimes called Implicit SSL) to encrypt the communication for the entire session. This is on port ID 465.
• Select TLS (sometimes called Explicit SSL) to begin the communication unencrypted.
  • Then the client issues a STARTTLS command to start using encryption before authenticating and sending the email.
• This is on various ports including port ID 25, 443, or 587.
  • If you select OAuth as the authentication method, the default selection is TLS, but you can change it.

Type the user ID to use to log on to the SMTP email server.

• If you SMTP server requires a domain name, type the domain name.
• This field appears when you select Basic in the Authentication Method field.

• Type the user ID password to log on to the SMTP email server.
• This field appears when you select Basic in the Authentication Method field.

• Retype the user ID password to confirm the password.
• This field appears when you select Basic in the Authentication Method field.

• Enter the client ID that will identify the application to the OAuth service.
• This field appears if you select OAuth in the Authentication Method field.

• Enter the client secret for the application on the OAuth service.
• This field appears if you select OAuth in the Authentication Method field.

• Enter the URL provided by the OAuth service that you use to obtain an authorization grant.
• This field appears if you select OAuth in the Authentication Method field.

• Enter the OAuth service URL to exchange an authorization grant for an access token.
• This field appears if you select OAuth in the Authentication Method field.

• Enter the scope of access as required by the OAuth service. If you're entering multiple scopes, separate them with a space.
• This field appears if you select OAuth in the Authentication Method field.

• Enter the callback URL.
• Leaving this field blank or entering http://localhost will work for most OAuth services.
• For OAuth services blocking localhost callbacks, enter a web server URL that redirects to http://localhost:3017.
• This field appears if you select OAuth in the Authentication Method field.

• Enter the required port number if the OAuth service listens for the redirect URI request.
• If the OAuth service doesn’t require a specific port, enter 0 (zero). The service will use a random port.
• This field appears if you select OAuth in the Authentication Method field.

• Select the option specified in the OAuth service requirements.
• This field appears if you select OAuth in the Authentication Method field.

• Select this check box to use the 128-bit encryption when you email password-protected documents.
• Clear this check box if you don’t want to use encryption for emails.