IPv4 vs IPv6 on iPhone: What's the Difference?
Short answer: IPv4 and IPv6 are two versions of the same thing, an address that identifies a device on the internet. IPv4 is the older, shorter format (203.0.113.42). IPv6 is the newer, much larger format (2001:db8::1). Your iPhone uses both automatically and you do not need to choose.
IPv4 vs IPv6 at a glance
| IPv4 | IPv6 | |
|---|---|---|
| Looks like | 203.0.113.42 | 2001:db8::1 |
| Size | 32 bits | 128 bits |
| Number of addresses | About 4.3 billion | Effectively unlimited |
| Numbers and separators | Four numbers, separated by dots | Hexadecimal groups, separated by colons |
| NAT needed? | Usually, because addresses ran short | Not needed for address sharing |
Why there are two
IPv4 has only about 4.3 billion addresses, which is fewer than the number of internet-connected devices. Home routers and mobile carriers stretch them with NAT, sharing one public address among many devices (see public vs private IP addresses). IPv6 was created to solve the shortage, with enough addresses that devices do not need to share.
Which one does your iPhone use?
Both. An iPhone on a network that supports both uses whichever is faster for each connection. Apple also requires apps in the App Store to work on IPv6-only networks, and many mobile carriers use IPv6 heavily, so you may be on IPv6 without knowing.
See both in Settings
- Open Settings > Wi-Fi and tap the (i) next to your network.
- The IPv4 Address section shows your IPv4 address, subnet mask and router.
- Scroll down. If the network supports IPv6, an IPv6 Address section lists one or more addresses.
If there is no IPv6 section, your router or ISP is not providing it on that network. That is common and not a problem.
See which one websites see
Open our home page. The IP type in the connection details tells you whether your connection used IPv4 or IPv6 to reach us. It can differ between Wi-Fi and cellular.
Does it matter which one I use?
- Speed: usually no noticeable difference. Your iPhone picks the faster path.
- Privacy: iOS uses temporary IPv6 addresses that change over time, so an IPv6 address does not follow you forever. For hiding your address, see how to hide your IP address.
- Compatibility: a few old devices and services only work with IPv4. Apple does not offer a simple switch to turn IPv6 off, and in most cases you should not need one.
How to read an IPv6 address
An IPv6 address is eight groups of hexadecimal numbers separated by colons. To keep them short, leading zeros in a group can be dropped, and one run of all-zero groups can be replaced by ::. So 2001:0db8:0000:0000:0000:0000:0000:0001 is written 2001:db8::1. Addresses starting with fe80 only work on your local network.
Common questions
Why does my iPhone show an IPv6 address but my router shows IPv4?
Routers and ISPs often run both at once. The router's login page may only list the IPv4 side.
Is IPv6 more secure than IPv4?
It is not automatically safer or less safe. Security depends on the router's firewall and your device updates, not the address format.
Do I need to do anything to use IPv6?
No. If your ISP or carrier supports it, your iPhone starts using it automatically.