What do the numbers used in a IPV6 address mean?

I am trying to understand IPV6. I have a server with the following IPV6 address: 2607:f750:0:3f::f59.

I don't understand what the numbers mean. It looks totally different from an IPV4 address.

Can anyone break it down for me?


IPv6 addresses are 128 bits. We don't do dotted decimal octet form any more.

2607:f750:0:3f::f59 is an abbreviated human-readable representation of an IPv6 address. The full human-readable representation substitutes zeroes for the ::, and is 2607:f750:0000:003f:0000:0000:0000:0f59. Each part of the address is very simple. It's a 16-bit number in hexadecimal form. There are eight of those, totalling to 128 bits.

In dotted-decimal-octet form, this would be 38.7.247.80.0.0.0.63.0.0.0.0.0.0.15.89. But IPv6 addresses are not conventionally presented in this form.

The most significant bits of this address place it in the so-called aggregatable global unicast portion of the IPv6 address space. That means that it is not a link-local or host-local address, and is not a broadcast or multicast address.

The most significant 12 bits identify a portion of the address space allocated by IANA to ARIN. The next 20 identify a subset of that space allocated in turn by ARIN to Distributed Management Information Systems, Incorporated (i.e. Pavlov Media). The next 32 indicate your particular subset of that, and the final 64 bits (0000:0000:0000:0f59) are an interface ID that denotes one individual network interface.

Pavlov Media telling you that you are assigned 2607:f750:0000:003f::/64 (if that is indeed what it told you) means that all valid combinations of the bottom 64 bits are assigned to you. The top 64 bits of your (non-local unicast) IPv6 addresses must be that prefix. Congratulations! You can put more devices on your LAN, and give them IPv6 addresses, than there are Ethernet cards in existence.

Further reading

  • R. Hinden, S. Deering (February 2006). IP Version 6 Addressing Architecture. RFC 4291. Requests for Comments.
  • R. Hinden, S. Deering, E. Nordmark (August 2003). IPv6 Global Unicast Address Format. RFC 3587. Requests for Comments.
  • IPv6 Global Unicast Address Assignments. IANA. 2008-08-27
  • NET6-2607-F750-1. WHOIS-RWS. ARIN.

An IPV4 address is a   32-bit integer number written like 192.168.1.6
An IPV6 address is a 128-bit integer number written like 2607:f750:0:3f::f59

2607:f750:0:3f::f59 is a short notation for a number that can be written in hexadecimal as

2607 f750    0   3f       ::        f59

i.e.

2607 f750 0000 003f 0000 0000 0000 0f59

or

2607f7500000003f0000000000000f59