When writing documentation, it is useful to provide examples. To avoid the examples from referencing real live resources, certain domain names and IP addresses have been set aside for use in documentation.
The domains reserved for documentation are:
.example(replace the "anything" portion with anything you like)
There are also several IP ranges set aside for documentation, including:
When writing documentation, it is recommended that you always use the example domains and IP addresses when creating examples, since users may accidentally try to use the examples provided, which can have undesired effects if you used a real domain name or IP address.
If you use a real domain name or IP address, it should be something that actually would work for the user.