IPv6 Expand & Compress
Expand to full notation, compress to the shortest RFC 5952 form, and get the ip6.arpa reverse-DNS record
2001:db8::/32 prefix shown by default is the RFC 3849 documentation range, reserved for examples.Frequently Asked Questions
How do I expand an IPv6 address to its full form?
A full IPv6 address is eight groups of four hexadecimal digits separated by colons. To expand a shortened address, restore the leading zeros in every group and replace the double-colon (::) with as many all-zero groups as are needed to reach eight groups total. For example, 2001:db8::1 expands to 2001:0db8:0000:0000:0000:0000:0000:0001.
How does IPv6 compression with the double colon work?
RFC 5952 defines the canonical short form: write each group in lowercase, drop the leading zeros in every group, then replace the single longest run of consecutive all-zero groups with a double colon (::). The :: may appear only once, and it must replace at least two groups. If two runs are equally long, the first one is compressed.
What is the ip6.arpa reverse-DNS form of an IPv6 address?
The ip6.arpa form is how reverse DNS (PTR) records are named for IPv6. Take the fully expanded 32-hex-digit address, reverse the order of the individual nibbles, separate each with a dot, and append .ip6.arpa. It is the IPv6 equivalent of in-addr.arpa for IPv4.