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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?

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Is it assigned locally (LAN) or is it an external IP from your ISP? –  BloodPhilia Jan 18 '12 at 12:50
This is what i see pastebin.com/W4Xy0efz i am not sure if it is an external ip. –  nestlee Jan 18 '12 at 12:54
It says i can provision a /64 subnet. whatever that means. –  nestlee Jan 18 '12 at 13:01
It means that you can put about 2**64 IPv6 devices on the internet. –  Ignacio Vazquez-Abrams Jan 18 '12 at 14:02
but each has to share 1 public ip. –  nestlee Jan 18 '12 at 14:54

3 Answers 3

up vote 16 down vote accepted

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 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

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Thanks very insightful. –  nestlee Jan 19 '12 at 6:51

An IPV4 address is a   32-bit integer number written like
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


2607 f750 0000 003f 0000 0000 0000 0f59


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It's just like IPv4 just much longer and with another notation... - written in a hex representation like IPv6 would only be 0101:0101 - ffff:ffff (that's not the actual representation of those IPv4 adresses, just for making the change in notation clear)

And if there are two colons :: that means all space between until the address is full-length is filled with zeros.

Doing this in IPv4 syntax:

1..1 ->

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IPv4 syntax would use 1.1, with only one dot. –  grawity Jan 18 '12 at 13:03

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