This extension allows you to authenticate a FE-User against a list of allow and/or deny IP adresses. Those black- and white-lists enable you to let only visitors log in into your website if their address matches a specific IP or IP range. The extension is very configurable using the extension manager, you can set in which order the allow/deny settings are checked and what the default behaviour is, when no IPs are set.
This extension is built for high performance. Whenever you set IP adresses they are checked upon saving the TCEform and get stored in an ip cache-table which allows very quick checks. This extension is a complete rewrite of the old "cc_ipauth" extension.