Audience: (ClassLink Administrator)
This article details how to set up SMTP between Gmail, GSuite, and OneSync email events & actions. SMTP is an Internet standard for email transmission. Proper setup is required to authorize OneSync to use your email service to send emails.
To begin, choose your configuration options based on what's supported by your device or application and then follow the appropriate steps based on your chosen option. The available options are:
- G Suite SMTP relay service: Send mail from your organization by authenticating with the IP addresses. You can send messages to anyone inside or outside of your domain.
- Gmail SMTP server: Send mail to anyone inside or outside of your domain. This option requires you to authenticate with your Gmail or G Suite account and password.
- Restricted Gmail SMTP server: Send messages to Gmail or G Suite users only. This option does not require you to authenticate.
|G Suite SMTP relay (recommended)||Gmail SMTP server||Restricted Gmail SMTP server|
|A registered G Suite user can't relay messages to more than 10,000 recipients per day. For full SMTP relay limits, see Sending limits for the SMTP relay service.||2,000 Messages per day. See Gmail sending limits.||Per user receiving limits apply. This option restricts sending messages to Gmail or G Suite users only.|
|Fully qualified domain name of SMTP service|
|Options: Port 25, 465, or 587||Port 465 (SSL required)||Port 25|
|Secure Socket Layer (SSL)/Transport Layer Security (TLS) protocols.||Port 587 (TLS required)||TLS not required|
|Dynamic IPs are allowed, but a static IP might be required due to authentication requirements.||Dynamic IPs allowed||Dynamic IPs allowed|
|Mail can only be sent to Gmail or G Suite users.|
|Either a static IP address or a valid G Suite user login||Your full Gmail or G Suite email address is required for authentication.||None|
GSuite SMTP relay (recommended)
- Add your network IP range to the SMTP relay service.
- Configure your device to connect to
smtp-relay.gmail.comon port 25, 465, or 587.
- For more details about using this setting, see SMTP relay service setting.
In order to send emails via an SMTP relay, you must edit your account permission settings to allow lower security clients to access your account. This requires that you login using an administrator account and two steps. The first involves routing outbound mail using the SMTP relay service. The second involves pointing your on-premise outbound server to Google. For more detailed steps to route outgoing non-Gmail messages through Google and more information, click here.
GMAIL SMTP server
If you connect using SSL or TLS, you can send mail to anyone with smtp.gmail.com. Note: Before you start the configuration, we recommend you set up App passwords for the the desired account. Learn more at Sign in using App Passwords and Manage a user's security settings.
- Connect to smtp.gmail.com on port 465, if you’re using SSL. (Connect on port 587 if you’re using TLS.)
- Sign in with a Google username and password for authentication to connect with SSL or TLS.
- Ensure that the username you use has cleared the CAPTCHA word verification test that appears when you first sign in.
Restricted Gmail SMTP server
If your device or application doesn’t support SSL, you can only send mail to Gmail or G Suite users.
Use the restricted SMTP server aspmx.l.google.com.
- Connect to aspmx.l.google.com on port 25.
- Configure an SPF record for your domain with the IP address of the device or application to ensure that recipients don’t reject mail sent from it.
- In your Google Admin console, add this IP address to the Email Whitelist box. For example, if your sending device sends from 18.104.22.168, add that address to your SPF record without removing the G Suite mail servers from the record: v=spf1 ip4:22.214.171.124 include:_spf.google.com ~all.
Note: To test your SPF record, use this Domain Name System (DNS) lookup tool.
Updated: Jan 2019