There are two sorts of IP addresses: IPv4 and IPv6 addresses.

An IPv4 address is a 32-bit number, usually written in "dotted quad" form, that is, as four 8-bit decimal numbers (0-255) separated by dots: 10.123.82.255.

In the DNS, the IPv4 address of each host is stored as an A record associated with the host's domain name.

An IPv6 address in its complete form is written in a form x:x:x:x:x:x:x:x, where each 'x' is at most 4 digits long hexadecimal value. A sequence of zero bits in IPv6 address might be shorten by ':: sign. For example: 1080:0:0:0:8:800:200C:417A and FF01::101 are IPv6 addresses.

In the DNS, the complete IPv6 might be stored as an AAAA record associated with the host's domain name. Alternatively part of the address might be stored in A6 record, which supports automatic reverse map creation, aggregation and network renumbering.