When you bind an macOS client to Active Directory, use names that follow these standards.
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.
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