How to whitelist an IP address that should not be checked against RBLs via WHM?

Realtime Blackhole Lists (RBLs) help block spam by checking incoming mail against databases of known spam sources. However, legitimate mail servers may sometimes appear on these lists. WHM allows you to whitelist specific IP addresses so they bypass RBL checks entirely, ensuring that mail from trusted servers is never incorrectly filtered.

Step 1: Log in to WHM

Open your browser and navigate to https://your-server-ip:2087. Log in with your root credentials.

Step 2: Open Exim Configuration Manager

Navigate to Home » Service Configuration » Exim Configuration Manager in the left-hand sidebar.

Step 3: Switch to the RBLs Tab

Click on the RBLs tab at the top of the Exim Configuration Manager page. This tab displays all currently configured RBLs and the whitelist option.

Step 4: Add IP Addresses to the Whitelist

Find the setting labeled Whitelist: IP addresses that should not be checked against RBLs. In the text box, enter one IP address per line. For example:

192.0.2.10
198.51.100.25
2001:db8::1

Both IPv4 and IPv6 addresses are supported.

Step 5: Save Changes

Click the Save button at the bottom of the page. The system will rebuild the Exim configuration and restart the mail service automatically.

Important Notes

• Use this feature sparingly. Only whitelist IP addresses of trusted mail servers that you control or have verified.
• You can also whitelist IP addresses in CIDR notation (e.g., 192.0.2.0/24) to cover entire ranges.
• Changes take effect immediately after saving.
• This whitelist only bypasses RBL checks. Other spam filtering mechanisms (SpamAssassin) will still apply.
• To remove an IP from the whitelist, simply delete it from the text box and save.

Troubleshooting

• Mail from a whitelisted IP is still being filtered: The issue may be caused by SpamAssassin rules rather than RBLs. Check your SpamAssassin configuration under Home » Service Configuration » Apache SpamAssassin.
• Cannot find the RBLs tab: Ensure your server uses a mail-enabled server profile.
• Exim fails to restart after saving: Review the Exim configuration for syntax errors in the Advanced Editor.

For official documentation, see the cPanel Exim Configuration Manager guide.