Private Wi-Fi addresses: what they hide and when to turn them off

Walk through an airport, a shopping center and a hotel lobby with Wi-Fi switched on, and your phone talks to each network it passes, even ones it never joins. Every one of those conversations includes a network address. For years, that address was the same everywhere, burned into the phone’s hardware. Anyone running several networks could recognize the same phone coming back, building a picture of where it went and when.

What the address is

To use a Wi-Fi network, a device has to identify itself with a hardware address, often called a MAC address. It’s not your IP address and it doesn’t go out to the internet. It’s only seen by the network you’re near and the equipment running it. That’s still a lot of places: shops, transport hubs, venues and their analytics providers.

A private address replaces the hardware one with a made-up address that’s unique to each network. The cafe sees one address, the airport another, your home router a third. None of them can link your visits together using the address alone.

How iPhone does it

Since iOS 14, iPhone uses a private address for each network by default. On iOS 18 and later, there are three settings per network:

• Fixed: a private address that stays the same for that network. The default for networks with strong security, such as most home networks.
• Rotating: a private address that changes about every two weeks. The default for open or weakly secured networks, like many cafes and hotels.
• Off: the phone’s hardware address.

To check or change it, open Settings, tap Wi-Fi, tap the info button next to the network, then Private Wi-Fi Address. On earlier versions it’s a single Private Address switch.

Erasing the phone or resetting network settings gives it new private addresses next time it joins each network.

How Android does it

Since Android 10, phones use a randomized address by default when they connect to a network. In the standard version, it’s a persistent address generated for each network, which stays the same for that network until the phone is reset, so networks that need to remember your device still can.

To check it, open Settings, go to Wi-Fi, tap the network to open its details, and look for a privacy option. You can choose between a randomized address and the phone’s own address. The exact wording varies between phone makers.

When to turn it off

Leave the private address on for every network that works with it. Turn it off only for a specific network that needs to recognize your phone, such as:

• a home network with parental controls or time limits tied to a device
• a school or work network that only admits approved devices
• a network that keeps disconnecting you or asking you to sign in again

Even then, turn it off for that network only. Both phones treat each network separately, so the others keep their protection. Before switching it off, the official iPhone guidance suggests installing the latest software update first, which often fixes the problem.

What a private address doesn’t hide

A private address is a narrow protection. It’s useful, but it doesn’t make you anonymous.

• Signing in identifies you. A hotel or cafe sign-in page that asks for your name, room number or email links the session to you.
• Your traffic is still visible to the network. The network can see which sites and services you connect to, though not the contents of encrypted connections.
• Apps and sites still know you. Once you sign in to an account, the address doesn’t matter.
• Other radios still talk. Wireless earbuds, watches and nearby sharing features have their own signals. See nearby sharing privacy settings.

Public Wi-Fi and your photos

People sometimes worry that joining a public network exposes the photos on their phone. A network can’t browse your gallery. The real risks on public Wi-Fi are signing in to fake pages and apps sending data unencrypted, both of which are rarer than they used to be. The bigger privacy questions for photos are which apps can read them and where they’re backed up. See which apps can see your photos.

Where Silo fits

Silo, coming soon to iPhone and Android, doesn’t need Wi-Fi or any network to keep your photos private. Its vault is encrypted on the phone, it has no account, and it never uploads your photos to us.