SMTP

Enabling SMTP

1. Tick the checkbox of Enable SMTP to deliver and receive emails.
2. Specify the following information:
   • Account type: Select one of the following account types to set up email addresses: local users, domain users, or LDAP users.
   • Enable SMTP Authentication: With this option enabled, you need to enter account credentials when setting up Mail Server on mail clients other than Mail Station.
     For example, on Outlook Express, you need to tick the checkbox of My server requires authentication in Tools > Accounts > Mail Account > Properties > Servers.
     It is recommended to enable this option to avoid being labeled as a spammer.
   • Ignore authorization for LAN connections: All connections except for LAN connections require user credentials for authentication.
   • Sender name and login name must be identical: A logged-in user has to use the email address that belongs to the login account to send emails.
   • Hostname (FQDN): Specify the domain name. For example, if you want to set up an email address like username@synology.com, you need to specify the Hostname (FQDN) as synology.com.
   • Port: Assign a port for the SMTP connection. The default port is 25.
   • Maximum size per email: Enter a number to specify the size limit.
   • Choose whether or not to send emails over a secure connection:
     • Enable SMTP-SSL
     • Enable SMTP-TLS
3. Click OK to save the settings.

Setting up Multiple Domain Names

You can map multiple domain names to your Mail Server (e.g., synology.com, synology.com.tw, and synology.com.us) to receive emails sent to various domains (e.g., username@synology.com, username@synology.com.tw, and username@synology.com.us).

1. Click Additional Domain.
2. Click the corresponding buttons to perform the desired actions.
3. Save the settings before closing the window.

Sending Emails via Other SMTP Servers

Most ISPs block or reject emails from unknown domains. If you cannot send emails directly from your domain, you may have to send them through a well-known SMTP server.

Follow the steps below to add a relay server:

1. Click SMTP Relay.
2. Tick the checkbox of Enable SMTP Relay.
3. Specify the Server and the Port number. Enter the server name with square brackets (e.g., [relay.net]) to skip redundant MX record lookup.
4. Choose whether or not to enable the following options:
   • Always use a secure connection (TLS): Relay emails over an encrypted connection.
   • Authentication required: Enter the account and password for the relay server.