Literal IPv6 addresses in UNC path names
In Microsoft Windows operating systems, IPv4 addresses are valid location identifiers in Uniform Naming Convention (UNC) path names. However, the colon is an illegal character in a UNC path name. Thus, the use of IPv6 addresses is also illegal in UNC names. For this reason, Microsoft implemented a transcription algorithm to represent an IPv6 address in the form of a domain name that can be used in UNC paths. For this purpose, Microsoft registered and reserved the second-level domain ipv6-literal.net on the Internet (although they gave up the domain in January 2014). IPv6 addresses are transcribed as a hostname or subdomain name within this name space, in the following fashion:
2001:db8:85a3:8d3:1319:8a2e:370:7348is written as
2001-db8-85a3-8d3-1319-8a2e-370-7348.ipv6-literal.netThis notation is automatically resolved locally by Microsoft software, without any queries to DNS name servers.
If the IPv6 address contains a zone index, it is appended to the address portion after an ‘s’ character:
fe80::1ff:fe23:4567:890a%3is written as
fe80--1ff-fe23-4567-890as3.ipv6-literal.netExtracted from https://en.wikipedia.org/wiki/IPv6_address#Literal_IPv6_addresses_in_UNC_path_names