Limit Sending via IP Allowlisting
The IP Allowlist feature improves account security by allowing you to restrict sending 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 through the SMTP2GO account with the following error message "550 that IP address on this account is not allowed to send".
The IP addresses to add will be the private IPs used by your company to access the internet.
To enable and add IP addresses to the IP Allowlist, navigate to the "Settings > Sending Options" page and click on the "IP Allowlist" tab.
Set the Enable IP Allowlist toggle to "On".
Click the "Add new IP address to allowlist" 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.
If you wish to further restrict sending to be from certain email addresses or domains only, please see our Restrict Senders feature.
Note: The IP Allowlist is unrelated to the IP Authentication feature.
If you have questions in regard to the IP Allowlist feature or any other part of your SMTP2GO account, please reach out to our award-winning support team for assistance by email ticket, live chat or phone.