Some days ago I’ve updated my WordPress to the new 3.8 version.

For storing my themes and plugins I’ve set up a repository on a virtual machine running on the same virtual network.

This was working perfectly until WordPress 3.5, but since 3.6 the developers added a new security feature that denies access to repository with a local ip, for example 172.[16-31].x.x as in my case, but also 127.0.0.1, 10.x.x.x, 192.168.x.x.

When I try to install or update a theme or plugin I’ve got this error:

Downloading install package from http://put.your-repository-domain-here.co/my/path/to/my/download
**Download failed. A valid URL was not provided.**

To add your repository to the allowed list you can simply add these lines to the very end of your wp-config.php.

<?php 

/** Enable my local themes and plugins repository FFS!!! */
add_filter( 'http_request_host_is_external', 'allow_my_custom_host', 10, 3 );
function allow_my_custom_host( $allow, $host, $url ) {
  if ( $host == 'put.your-repository-domain-here.com' )
    $allow = true;
  return $allow;
}

• Be advise that the php open tag may not be required.
• Check also that the given code is placed after: require_once(ABSPATH . 'wp-settings.php');
• Don’t mind the warning: /* That's all, stop editing! Happy blogging. */