If your printer, scanner, or application needs to send emails via SMTP, you can configure it to send mail using the Google Apps mail servers.
For details about configuring your device or application to send SMTP messages, refer to its documentation.
See also "Using the SMTP relay service" below.
You can connect to the Google Apps mail servers using SMTP or SSL. If you connect using SMTP, you can only send mail to Gmail or Google Apps users; if you connect using SSL, you can send mail to anyone.
If your device or application supports SSL, connect to smtp.gmail.com on port 465 or 587.
To connect with SSL, you need to provide a Google username and password for authentication. We recommend that you use a separate account, such as scanner@, so that passwords are kept secure and you do not run the risk of a user leaving. Ensure that the username you use has cleared the CAPTCHA word verification test that appears when the user first logs in. We also recommend ensuring that the account has a secure password.
If your device or application does not support SSL, connect to aspmx.l.google.com on port 25.
You must configure an SPF record for your domain with the IP address of the device or application to ensure that recipients do not reject mail sent from it. For example, if your sending device sends from 188.8.131.52, add that address to your SPF record without removing the Google Apps mail servers from the record:v=spf1 ip4:184.108.40.206 include:_spf.google.com ~all
Using the SMTP relay service
Another way to configure your device or application to send messages via TLS or SMTP through Google Apps is to use the SMTP relay service setting in the Google Admin console. This is possible once you add your network IP range to the SMTP relay service. You would need to configure your device to connect to smtp-relay.gmail.com on ports 25 or 465.