School Wifi Tracking: What Happens When You Disconnect?

G5 Cyber Security

1 week ago

TL;DR

Generally, a school wifi network can’t continuously track your device after you disconnect from the wifi. However, they might still be able to see some information about when you connected and disconnected, and potentially identify your device if it has previously registered with the network. It depends on their setup.

Understanding How School Wifi Works

School wifi networks are usually designed for security and monitoring. Here’s a breakdown of what they can and can’t do:

When Connected: When you connect to the school wifi, your device gets an IP address (a unique number) and communicates with the network server. The school can see which websites you visit (often logged), how much data you use, and potentially even some of the content you’re accessing if they use deep packet inspection.
When Disconnected: When you disconnect, your IP address is released back into the pool for others to use. This means direct tracking via that IP address stops.

What Information Can a School Still See?

Even after disconnecting, schools can potentially see:

Connection Logs: Most school networks keep logs of when devices connect and disconnect. This log will show the date, time, and often the MAC address (a unique identifier for your device’s network adapter).
MAC Address Identification: Your MAC address is like a serial number for your device’s wifi card. If you’ve connected to the school wifi before, they can identify your device even if you change networks or disconnect. However, it’s possible (though often difficult) to spoof or change your MAC address – see step 5 below.
Captive Portal Data: If the school uses a captive portal (a login page you see when connecting), they have any information you entered during registration (name, student ID, etc.). This isn’t related to tracking *after* disconnection but is data they already possess.

Steps to Limit Tracking

Here’s what you can do to reduce the amount of information the school can collect:

Use a Personal Hotspot: The most effective way is to use your phone’s personal hotspot or another wifi network that isn’t controlled by the school. This completely bypasses their system.
VPN (Virtual Private Network): A VPN encrypts your internet traffic and hides your IP address from the school’s network. While they can see you’re using a VPN, they can’t see what websites you’re visiting. Be aware that some schools block VPN connections.
Avoid Connecting to School Wifi: If possible, avoid connecting to the school wifi altogether for activities where privacy is important.
Clear Browser History and Cookies: Regularly clear your browser history, cookies, and cache. This won’t prevent network-level tracking but will remove traces of your activity from your device.
MAC Address Spoofing (Advanced): You can change your MAC address on most devices. This is a more technical process and may violate school policies. Here’s how to do it on Windows:
```
netsh wlan show interfaces
```
Note the interface name (e.g., Wi-Fi). Then use:
```
netsh wlan set macaddress name="Wi-Fi" address=XX-XX-XX-XX-XX-XX
```
(Replace “Wi-Fi” with your interface name and XX-XX-XX-XX-XX-XX with a randomly generated MAC address.) On macOS, you can find instructions online for changing the MAC address through System Preferences.

Important Considerations

School Policies: Always check your school’s policies regarding wifi usage. Attempting to bypass security measures could have consequences.
Network Monitoring Tools: Schools may use sophisticated network monitoring tools that go beyond simple connection logs.
Legal Aspects: Schools generally have a legitimate interest in monitoring their networks for security and safety reasons, but there are limits to what they can do.