1. SentryFi
2. WiFi guides
3. Private WiFi address

What a private WiFi address is

Every WiFi chip has a hardware address, called a MAC address, that it shows to every network it talks to. Because it doesn’t change, the same address seen at a café, an airport and a shopping centre can link those visits to one device. A private (randomized) address replaces it with a different one per network. It is a privacy feature: it doesn’t encrypt your traffic or make an unsafe network safe.

iPhone: Off, Fixed or Rotating

Apple’s support page describes three options in iOS 18, iPadOS 18, visionOS 2 and later:

Earlier versions (iOS 14 to iOS 17) only have an on/off switch. Apple adds that your device chooses Rotating by default when it joins a new network that uses weak security or no security.

1. Open the Settings app, then tap Wi-Fi.
2. Tap the More Info button (the “i”) next to the network.
3. Tap Private Wi-Fi Address, then choose Off, Fixed or Rotating. On iOS 17 or earlier, turn the switch on or off.

The setting is per network, so you can use Rotating at the airport and Fixed at home. If you forget a network, the private address for it is forgotten too (on iOS 18 and later, unless you rejoin within 24 hours).

Android: randomized MAC address

Google’s help page says phones with Android 10 and above use another MAC address, and Android’s developer documentation confirms that randomization is on by default. To check or change it for one network:

1. Open Settings > Network & internet > Internet.
2. Tap the settings icon next to your network.
3. Scroll to Randomized MAC address (search Settings for “MAC address” if your phone’s menus differ).

By default Android uses persistent randomization: one made-up address per network, kept until a factory reset, which works like Apple’s Fixed. Since Android 12, Android can use non-persistent randomization for open networks that haven’t shown a sign-in page and when an app requests it. In that mode the address can change on reconnect, if the DHCP lease has expired and more than 4 hours have passed, or if the address is more than 24 hours old.

When to turn it off (or use Fixed)

• A home router that only lets known devices join (a MAC allow-list) or parental controls that identify devices by address. Fixed usually solves this without turning privacy off.
• Hotel or campus WiFi that keeps logging you out. Some sign-in systems remember devices by address; a rotating address can look like a new device. Try Fixed for that network.
• Work or school networks that require it. Organisations can turn the feature off through a network profile on managed devices.

Apple suggests installing the latest software updates and trying again before deciding to turn the feature off, because most networks work fine with it on. If a hotel or airport sign-in page won’t load, see the iPhone and Android fixes.

What it doesn’t do

A private address doesn’t hide what you do online from the network: the network still sees which sites you connect to (unless you use a VPN or a service like iCloud Private Relay), and it doesn’t stop a lookalike network from showing you a fake sign-in page. The FTC’s advice for public WiFi still applies: use encrypted apps and sites, and don’t ignore warnings. SentryFi doesn’t change phone or router settings. It checks the network you are on for warning signs — an unexpected sign-in page, DNS answers that differ from trusted DNS, certificate problems, a hidden proxy — and gives a 0–100 risk score with plain next steps.