Our NT Domain service is provided by a pair of NT servers which are our Primary Domain Controller (PDC) and a Backup Domain Controller (BDC). These machines are also our Windows Internet Name Service (WINS) servers. We have ``engineered them for reliability'' in stupid, brute force ways because, unlike our UNIX servers, they can not easily be remotely rebooted or maintained. For example, installing new software often requires a reboot. Reliability is achieved by running no other services on them. We are unhappy that reliability has to be achieved this way. We are investigating other options: new software for UNIX servers that turn them into PDCs; replacing NT Domain all-together with Light-weight Directory Access Protocol (LDAP) [RFC2251], an open standard for directory services; and other options.
Domain Name Service (DNS) [RFC1035] and Dynamic Host Configuration Protocol (DHCP) [RFC2131] services are provided by our existing UNIX servers. We require authenticated logins (single-use passwords via Hand Held Authenticators) to these machines since so much depends on DNS being reliable and authentic. For DHCP we use ISC's free DHCP reference implementation [DHCP] and are extremely happy with its flexible configuration file format. We actually generate the configuration file from our NIS data with a perl script. SAs don't actually have to know how to modify the DHCP database. They enter certain information and a perl script generates the rest. We also use the ISC ``BIND'' DNS software [BIND].