Using IPv6 Addresses in URLs

IPv6 addresses contain colons. Colons, however, are also used in other types of network addressing syntax. For example, IPv4 uses a colon to separate IP address and port number when both are used in a URL. IPv6 has inherited this principle. Therefore, to avoid confusion, square brackets are put around IPv6 addresses when they are used in URLs.

Example of a URL with an IPv6 address:
http://[2001:0B80:0000:0000:0000:0F80:3FA8:18AB], which may of course be shortened to, for example, http://[2001:B80::F80:3FA8:18AB]

Example of a URL with an IPv6 address and a port number:
http://[2001:0B80:0000:0000:0000:0F80:3FA8:18AB]:1234, which may of course be shortened to, for example, http://[2001:B80::F80:3FA8:18AB]:1234

For more information about IPv6, see, for example, the IANA website (https://www.iana.org/numbers/). IANA, the Internet Assigned Numbers Authority, is the organization responsible for the global coordination of IP addressing.