# Alias Domain Authentication In order to allow website visitors to login to user accounts on mapped subdomains of your website, you can simply enable the checkbox for *Alias Domain Authentication:*

This will allow users to login to Alias Domains of your website and remain only logged in to that Alias Domain. They are only able to access protected login pages that are mapped to the specified alias. ### Selective Alias Domain Authentication The dropdown checkbox allows you to selectively activate Alias Domain Authentication only on specific alias domains:

Activating Subdomain Authentication on Specific Subdomains

### Multisite Requirements If you are trying to configure Alias Domain Authentication on multisite, you must update the sunrise.php file mentioned in our [multisite integration](https://domainmappingsystem.gitbook.io/domainmappingsystem-docs/features/multisite-integration) docs to change this string from this: ``` if ( ! is_multisite() || $is_admin ) { return $site; } ``` To this: ``` if ( ! is_multisite() || ! $is_admin ) { return $site; } ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://domainmappingsystem.gitbook.io/domainmappingsystem-docs/features/alias-domain-authentication.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.