IPv6 Address Format

We know the IPv6 address size is 128 bits. The preferred IPv6 address representation is: x:x:x:x:x:x:x:x, where each x is the hexadecimal values of the eight 16-bit pieces of the address. IPv6 addresses range from 0000:0000:0000:0000:0000:0000:0000:0000 to ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff.

In addition to this preferred format, IPv6 addresses might be specified in two other shortened formats:

Omit leading zeros

Specify IPv6 addresses by omitting leading zeros. For example, IPv6 address 2302:0000:0000:0000:0005:0000:300c:326b can be written as 2302:0:0:0:5:0:300c:326b

OR,

Double colon

Specify IPv6 addresses by using double colons (::) in place of a series of zeros. For example, IPv6 address 2302:0:0:0:5:0:300c:326b can be written as 2302::5:0:300c:326b

Mind it,

Double colons can be used only once in an IP address. So if you write the above address like below:

2302::5::300c:326b. ## This is wrong. Because of double colon appears twice here.

The loopback Address:

     IPv4 Format- 127.0.0.1/8

     IPv6 Format- ::1/128

We will discuss about the address type of IPv6 in next post.