The IP Allowlists feature improves account security by allowing you to restrict sending via SMTP or API (this includes all API calls) to be from allowed IP addresses only. If you choose to enable the IP Allowlist, any IPs that are not listed will be blocked from sending or making API calls through the SMTP2GO account with the following error message "550 that IP address on this account is not allowed to send" or "This request is coming from an IP address that isn't in the IP allow list".
The IP addresses to add will be the private IPs used by your company to access the internet.
How to enable and manage the IP Allowlists
To enable and add IP addresses to the IP Allowlists, navigate to the "Settings > Sending Options" page and click on the "IP Allowlist" tab.
Set the "Enable SMTP Allowlist" or "Enable API Allowlist" toggle to "On" for your desired allowlist.
Click the "Add IP address" button and enter the IP address or IP range and description (optional), then click "Save". Note: You can add a singular IP address or an IP range (CIDR notation).
Repeat the process if you need to add multiple IPs or IP ranges.
Finally, click the "Save Changes" button on the IP Allowlist page.
To remove an IP from the allowlist, click the "X" button on the far right side of the row and click "Remove".
You can alternatively manage the IP Allowlist via the API - detail is covered in our API documentation.
Additional information
To further secure your account, you can use the Restrict Senders or Recipients features to:
- Allow sending or disallow sending from the addresses or domains listed.
- Only allow sending to the listed recipient email addresses or domains.
Note: The IP Allowlist is unrelated to the IP Authentication feature.
If you have questions regarding the IP Allowlists feature or any other part of your SMTP2GO account, please reach out to our award-winning support team for assistance.