To make sure that the computer binds with System Preferences, Directory Utility, or dsconfigad, use computer names that:
- are less than 16 characters long.
- have only alphanumeric (A–Z, a–z), numbers (0–9), - (dash) and/or _ (underscore) characters.
Don't enter a longer computer name or invalid characters. If you do, a client might not bind to Active Directory. Or, macOS might bind to Active Directory with a truncated computer name.
The underscore character is valid in host names but not in a DNS domain name. If an Active Directory domain name has an underscore, binding and services won't work.