Reading and Shortening IPv6 Addresses

An IPv6 address is 128 bits written as eight groups of four hexadecimal digits, separated by colons. Each group represents 16 bits, and eight times 16 is 128.

An example is 2001:0db8:0000:0000:0000:ff00:0042:8329. The colons replace the dots used in IPv4 notation.

IPv6 uses hexadecimal (base 16), with digits 0-9 and letters a-f. The letter a equals 10, b is 11, up to f which is 15.

Each hex digit represents 4 bits, so four hex digits make 16 bits — one group. Hexadecimal keeps the long 128-bit address compact and human-readable.