IP Addresses and Domain Names to Use in Examples and Documentation

From https://tools.ietf.org/html/rfc2606
The Internet Assigned Numbers Authority (IANA) also currently has the following second level domain names reserved which can be used as examples.
From https://tools.ietf.org/html/rfc5737
The blocks (TEST-NET-1), (TEST-NET-2), and (TEST-NET-3) are provided for use in documentation.
From https://tools.ietf.org/html/rfc3849
The prefix allocated for documentation purposes is 2001:DB8::/32

General documentation