A domain name is the name assigned to a group of systems on a local network that share DNS administrative files. A domain name is required for the network information service database to work properly.
DNS obtains your default domain name from your resolv.conf file.
If the resolv.conf file is not available, or does not identify a default domain, and if your enterprise-level name service is either NIS+ or NIS, the Sun implementation of DNS obtains the default domain name from those services.
If resolv.conf is not available or does not provide a domain name and you are not running either NIS+ or NIS, you must either provide a resolv.conf file on each machine that does specify the domain (see "The Resolver"), or set the LOCALDOMAIN
environment variable.
When working with DNS-related files, follow these rules regarding the trailing dot in domain names:
Use a trailing dot in domain names in hosts, hosts.rev, named.ca, and named.local data files. For example, sales.doc.com. is correct for these files.
Do not use a trailing dot in domain names in named.boot or resolv.conf files. For example, sales.doc.com is correct for these files.