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Subdomains & subdirectories

By default, all WordPress multisite environments on the VIP Platform are configured with a  subdirectory structure. The SUBDOMAIN_INSTALL constant is defined at platform level in wp-config.php with a default of value of false. This value cannot be overridden, even by defining the constant differently in vip-config.php or with any other methods.

To achieve the same effect as a subdomain multisite, custom domains and subdomains can be mapped to network sites (e.g., The URL for an existing network site can be edited and replaced with an entirely new URL, including a subdomain structure. When updating a network site to be reachable at a custom domain or subdomain, it is recommended to first add and map the domain to the environment so that the network site is web-accessible. If a network site URL is updated to a custom domain that is not yet added and pointed to the VIP environment, it will only be accessible by modifying a hosts file.

The Network Sites launch tool in the VIP Dashboard is recommended for updating a network site’s address URL structure.

A combination of both subdomain and subdirectory URL structures for network sites can exist within a single multisite such as:

  • A collection of network sites with only subdirectory structures (e.g., and
  • A collection of network sites with assigned custom domains and subdomains (e.g., and
  • A collection of network sites that include both subdirectory and subdomain structures (e.g.,,, and


By default the VIP Platform supports a subdirectory site with a single segment path (e.g.,

A subdirectory site path with a maximum of two segments (e.g., can be enabled through code using the site_by_path_segments_count filter.

In the code example below, $num_segments = 3; sets the subdirectory structure to allow

  1. the custom domain
  2. the first subdirectory
  3. and the second subdirectory.

Integers higher than 3 are not allowed. A version of the code example below should be added to /vip-config/client-sunrise.php:

function my_filter_site_by_path_segments_count( $num_segments ) {
        $num_segments = 3;
        return $num_segments;
add_filter( 'site_by_path_segments_count', 'my_filter_site_by_path_segments_count', 99 );

Last updated: April 03, 2023

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