In a corporate environment all servers get joined to the active directory domain. I’m not talking about “querying” AD like un user management. I’m talking about what you can/would do with any linux server.
How to join a Linux system to an Active Directory domain | Enable Sysadmin (redhat.com)
How to join a Linux computer to an Active Directory domain - TechRepublic
Is there any reason this can’t be done with a FreePBX system (based on the FreePBX ISO)?