Install
This is the repository archive. It installs, but the folder name will carry the branch suffix and updates will not flow.
Install straight from GitHub with WP-CLI:
wp plugin install https://github.com/pluginsclub/rbl-checker/archive/refs/heads/main.zipNo built-in updater. New versions won't appear under Dashboard → Updates. Install new releases yourself, or let Git Updater track the repository.

RBL Checker allows anyone to check if an IP address or domain is listed in RBLs. To include the check field on any page, simply add the shortcode [rbl]

RBL Checker is also available as a cPanel plugin.