How to add an IP address as Trusted SMTP IP address via WHM?

Overview

The Trusted SMTP IP addresses setting in WHM's Exim Configuration Manager allows you to specify IP addresses that your server should trust for sending mail without applying certain spam filtering restrictions. Trusted IPs bypass rate-limiting rules and are excluded from some Exim ACL checks, making this useful for mail relays, third-party mail services, and backup MX servers that deliver legitimate mail to your server.

Step 1: Log in to WHM

Log in to your WHM interface as the root user or a reseller with sufficient privileges. You can access WHM by navigating to https://your-server-ip:2087 in your browser.

Step 2: Open the Exim Configuration Manager

In the WHM sidebar, navigate to:

Home » Service Configuration » Exim Configuration Manager

Step 3: Switch to the Basic Editor

Click the Basic Editor tab at the top of the page if it is not already selected.

Step 4: Locate the Access Lists Section

Scroll down or use the search box to find the Access Lists section. Within this section, locate the option labeled Trusted SMTP IP addresses.

Step 5: Add the IP Address

Click the Edit button next to Trusted SMTP IP addresses. In the popup that appears, enter the IP address you want to trust. You can add multiple IP addresses, one per line. CIDR notation (e.g., 192.0.2.0/24) is supported for trusting entire ranges.

Step 6: Save and Apply

Click Save in the popup box, then click Save at the bottom of the Exim Configuration Manager page to apply your changes. The server will rebuild the Exim configuration automatically.

Important Notes

• Root access required — Only root-level users can modify Exim configuration settings.
• Use with caution — Trusted IPs bypass certain security checks. Only add IP addresses of mail servers you control or fully trust (e.g., your backup MX server or a known mail relay).
• Automatic trusted servers — cPanel & WHM automatically adds remote MX, smarthost, and email relay servers that send mail to local domains to the trusted list. Apache SpamAssassin will not scan incoming mail from these automatically trusted servers.
• CIDR notation — You can specify IP ranges using CIDR notation (e.g., 10.0.0.0/24) instead of listing individual addresses.

Troubleshooting

• Changes not taking effect — After saving, you may need to restart Exim. You can do this by running service exim restart via SSH or WHM Terminal.
• Mail still being rate-limited — Verify the IP address is entered correctly. Check the Exim mail log at /var/log/exim_mainlog for clues about which ACL rule is blocking or delaying the connection.

For the official cPanel documentation, visit the Exim Configuration Manager - Basic Editor page.