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If you want to block people from certain (obscure) countries that have no business visiting your blog and perhaps only leave spam comments or other harmful actions than this is the plugin for you.

Choose which countries you want to ban from visiting your blog. Any visitors from that country get a HTTP/403 error with the standard message "Forbidden - Users from your country are not permitted to browse this site." The message is customizable.

They will not be able to do harmful things to your blog like post comment spam.

This plugin uses the GeoLite database from Maxmind. It has a 99.5% accuracy so that is pretty good.

Once you setup this plugin it will try to download the GeoIP database from Maxmind so you will always have a recent version of the database when installing this plugin.