WordPress at a glance
filter is not described

allowed_redirect_hosts filter-hook . WP 2.3.0

Filters the list of allowed hosts to redirect to.

Usage

add_filter( 'allowed_redirect_hosts', 'filter_function_name_4674', 10, 2 );
function filter_function_name_4674( $hosts, $host ){
	// filter...

	return $hosts;
}
$hosts(string[])
An array of allowed host names.
$host(string)
The host name of the redirect destination; empty string if not set.

Changelog

Since 2.3.0 Introduced.

Where the hook is called

wp_validate_redirect()
allowed_redirect_hosts
wp-includes/pluggable.php 1480
$allowed_hosts = (array) apply_filters( 'allowed_redirect_hosts', array( $wpp['host'] ), isset( $lp['host'] ) ? $lp['host'] : '' );

Where in WP core the hook is used WordPress

wp-includes/pluggable.php 75
add_filter( 'allowed_redirect_hosts', 'redirect_this_site' );