Understanding DNS Requirements for Exchange Server 2003
In Active Directory, all client logons and lookups are directed to local domain controllers and GC servers through references to the SRV records in DNS. Each configuration has its DNS and resource requirements. In a member server configuration, Exchange relies on other servers for client authentication and uses DNS to find those servers. In an Active Directory domain controller configuration, on the other hand, the Exchange server also participates in the authentication process for Active Directory.
Exchange 5.5 and E2k3 DNS/WINS Name Resolutions Requirements
Exchange 5.5 and NT4 use different name resolution orders when trying to resolve a name. NT4 relies on the local hostname, HOST, DNS ...