I have a new notebook with Windows Vista Home Premium installed. I noticed
when I view Network Properties, I see that Internet Protocol Version 6 (TCP/IP
v6) has been selected as well as TCP/IP v4. What is TCP/IP v6? Do I need it to
search the web?
You don’t need it yet, but someday you will. How soon? Good question.
Because 4 billion isn’t a big enough number.
Become a Patron of Ask Leo! and go ad-free!
IP, or “Internet Protocol”, is best recognized by the way it assigns “IP
addresses” to devices on the internet. An IP version 4 address, the current
common technology, is a 32 bit number, represented by 4 numbers separated by
periods. 22.214.171.124 is an example of an IP address (this one, assigned to
the domain microsoft.com).
A 32 bit number can represent up to 4 billion different IP addresses. In
reality the number is somewhat less, since some numbers and digits have
As it turns out, 4 billion isn’t enough. Because of the way that IP
addresses are assigned and used, I’ve heard we may “run out” of IP addresses in
Enter IP version 6, or IPv6. IP version 6 introduces many additional
features, but the most notable one is that an IPv6 address is 128 bits long
instead of 32. While that seems like it’s only 4 times larger, it’s not. It
represents 3.4×1038 different IP addresses.
Put another way:
IPv4: 4,294,967,296 addresses
IPv6: 340,282,366,920,938,463,463,374,607,431,768,211,456 addresses.
(That’s 4 billion times 4 billion times 4 billion times 4 billion – where “4
billion” is in computer terms using powers of 2, or 4,294,967,296.)
When you start seeing them, you’ll see IPv6 addresses as groups of 4
hexadecimal digits separated by colons. 2001:0db8:85a3:08d3:1319:8a2e:0370:7334
is a valid IPv6 address. It turns out they’ve also created some shorthand so
all IPv6 addresses, while still 128 bits in length, may not be represented by a
string quite that long.
We’re not likely to run out of IPv6 addresses any time soon.
Will you be forced to switch? Someday, maybe. The good news is that for now
it’s pretty transparent, and you probably won’t be affected for some time.
There actually is some IPv6 traffic on the internet already, using techniques
to coexist with the IPv4 traffic.
The fact that you’re seeing an IPv6 protocol available within Windows is
actually good news, because it means that one major part of the infrastructure
of the internet – millions and millions of Windows based PCs – are ready to
But for now, I’d just leave it enabled and otherwise ignore it.