Reserved DNS names
RFC 6761 reserves the following four top-level domain names to avoid confusion and conflict. Any such reserved usage of those TLDs should not occur in production networks that utilize the global domain name system:
- example: reserved for use in examples
- invalid: reserved for use in obviously invalid domain names
- localhost: reserved to avoid conflict with the traditional use of localhost as a hostname
- test: reserved for use in tests
In addition, RFC 6762 reserves the use of .local for link-local host names that can be resolved via the Multicast DNS name resolution protocol.
Example.com, example.net, example.org, and example.edu are second-level domain names reserved for documentation purposes and examples of the use of domain names.