Start with the shape of the address
An IP address identifies where internet data should be delivered. IPv4 is familiar and remains widely used, but it has a limited number of possible addresses. As the number of connected devices grew, IPv6 was introduced with a much larger address space.
IPv4 and IPv6 at a glance
| Item | IPv4 | IPv6 |
|---|---|---|
| Address length | 32 bits | 128 bits |
| Notation | Four numbers from 0 to 255, separated by dots | Hexadecimal groups separated by colons |
| Example | 198.51.100.7 | 2001:db8::7 |
| Address capacity | About 4.3 billion | Vast enough for current needs |
| Use today | Still widespread | Growing by network and service |
Why do we still use both?
IPv4 could not disappear as soon as IPv6 arrived. Older routers, business equipment, and online services may support only IPv4, and replacing every connected system at once is not practical. Many networks therefore operate in dual-stack mode and offer both protocols.
A browser can choose IPv6 when both your connection and the destination support it; otherwise it can connect over IPv4. The address type shown on one device can even vary from site to site.
Some networks translate between formats
An IPv6-oriented network may translate traffic when you open an IPv4-only service. This is usually transparent, but direct inbound features such as remote access or a game server may be restricted.
Long IPv6 addresses still follow clear rules
A full IPv6 address has eight hexadecimal groups using 0–9 and a–f. Leading zeroes in a group may be omitted, and one consecutive run of all-zero groups may be shortened to ::. The same address can therefore have a long and a compressed form.
- Uppercase A–F and lowercase a–f represent the same values.
- :: stands for omitted all-zero groups and may be used only once in an address.
- When an IPv6 address and port appear together in a URL, the address is enclosed in square brackets.
Check whether your connection uses IPv4 or IPv6
Check my IP displays the format used for the current page connection. An address made of numbers and dots is IPv4; a longer address containing colons is IPv6.
Not seeing IPv6 does not mean the internet is broken. If your provider, router, or the destination does not support IPv6 on that path, IPv4 can work normally. If IPv6 is displayed, that connection path is using IPv6.
Do you need to choose one?
For ordinary browsing, the operating system and browser usually choose the appropriate format automatically. You mainly need to pay attention when a server allowlist, remote desktop, game server, or DNS configuration requires a particular address type.
Frequently asked questions
If I see IPv6, have I stopped using IPv4?
Not necessarily. Many connections provide both IPv4 and IPv6, and the device chooses a format supported by the destination.
Is IPv6 always faster?
The address format alone does not guarantee speed. Performance depends on the network route, router, provider, and destination support.
What does a double colon mean in an IPv6 address?
It shortens one consecutive run of zero groups. This compression can appear only once within a single IPv6 address.