What is the difference between IPv4 and IPv6?
IPv4 addresses look like 203.0.113.10, four numbers separated by dots in a 32-bit format, while IPv6 addresses look like 2001:db8::1, a longer 128-bit format separated by colons. IPv6 is being adopted as IPv4 addresses run short.
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What does an IPv4 address look like?
IPv4 (Internet Protocol version 4) uses four numbers from 0 to 255 separated by dots to form a 32-bit address, written like 203.0.113.10.
A 32-bit space allows only 2^32, about 4.3 billion addresses, and the number of internet-connected devices has long passed that. That is why most homes use a private IP behind one shared public IP.
What does an IPv6 address look like?
IPv6 uses a much larger 128-bit format, written as eight groups of hexadecimal digits separated by colons, such as 2001:db8::1, with runs of zeros shortened to ::.
128 bits provides a space so large that exhaustion is essentially not a concern, so more providers now hand out a public IPv6 address per device.
Why is IPv4 still used alongside IPv6?
Not every website and device switched to IPv6 at once, so most providers and routers run dual-stack, supporting IPv4 and IPv6 at the same time.
To make IPv4 addresses stretch further, some providers share one public IP across many subscribers, a technique called CGNAT.
How do I check whether I have IPv4 or IPv6 on ipnow.kr?
The ipnow.kr homepage shows your IPv4 address, IPv6 address, or both, depending on how your connection reaches the internet. You can tell right away whether your provider also gave you a public IPv6 address.
Curious about the provider and ASN shown next to your IP? See what is an ASN.
| Item | Value | Source |
|---|---|---|
| Number of IPv4 addresses | 2^32 ≈ 4.3 billion | RFC 791 · 1981-09 |
| IPv6 address length | 128 bits | RFC 8200 · 2017-07 |
Frequently asked questions
Is IPv4 or IPv6 faster?
Speed depends far more on your provider and the server you connect to than on the IP version itself, though some large sites route IPv6 traffic over shorter paths.
How do I know if I have IPv6 at home?
If ipnow.kr shows a long colon-separated address alongside your IPv4 address, you have IPv6. If not, your connection is still IPv4 only.
Does IPv6 have private addresses too?
Yes, IPv6 has its own scheme for local addressing, but you will check IPv4 private addresses like 192.168.x.x far more often at home.
Have IPv4 addresses really run out?
The pool of freely available IPv4 addresses is essentially exhausted in most regions, which is one reason providers rely on CGNAT and IPv6 together.
How can I tell if my device supports IPv6?
Most Windows, Mac, and phone devices released in recent years support IPv6 by default. Whether you actually receive an IPv6 address depends more on your provider and router settings, so checking ipnow.kr directly is the most reliable way to know.