Comment by p_ing

7 hours ago

Usage of .local for AD predated mDNS. That advice stopped with the advent of mDNS in favor of 'corp.<registered_domain>.<tld>'.

The original Windows 2000 guidance for AD was corp.example.com, from my recollection. The silly .local thing (which does predate mDNS) happened as a result of the Small Business Server refresh for Active Directory.