Under the premise of complying with laws, regulations and ethics, it is necessary to be cautious to permanently disable Internet access to a certain computer. The following are several technical solutions and their precautions： --- ### **1. Router/firewall configuration** -**Method**： Filter the MAC address/IP address on the router or firewall of the local area network to permanently prohibit the device from networking. -**Advantages**： -Do not modify the target device hardware or system. -Reversible (the administrator can lift the restriction at any time). -**Restrictions**： -Only valid for the current local area network, the device can still be connected to the Internet through other networks (such as mobile hotspots). -Administrator privileges are required. --- ### **2. Operating system-level restrictions** -**Method**： -**Windows**: Through group policy (`gpedit. msc`) Disable the network adapter or set an invalid proxy. -**macOS/Linux**: Disable network services or modify routing tables through the terminal. -**Advantages**： -No hardware changes are required. -**Restrictions**： -Administrator privileges are required. -Reinstalling the system or resetting the network configuration can be restored. --- ### **3. Physical isolation (non-destructive)** -**Method**： Remove or disable the network card (such as disable the built-in network card through the BIOS, or unplug the external network card). -**Advantages**： -High reliability of physical isolation. -**Restrictions**： -It may affect the portability of the laptop. -The user can re-enable the network card or use the USB network card. --- ### **4. DNS hijacking or Hosts file modification** -**Method**： Modify the `hosts` file of the target computer to resolve the commonly used domain name to an invalid IP. -**Advantages**： -Simple and easy. -**Restrictions**： -Only domain name access is blocked, and direct IP connection is still valid. -Administrator rights are required, and the user can modify it back. --- ### **5. Enterprise-class solution** -**Method**： Use MDM (mobile device management) or terminal management software (such as Jamf, SCCM) to force the push of network policies. -**Applicable scenarios**： -Enterprises or educational institutions implement control over managed equipment. --- ###**Precautions** 1. **Law and Ethics**： -Unauthorized use of other people's devices may violate laws (such as the Computer Fraud and Abuse Act, etc.). -Only for legal scenarios (such as company asset management, parental control). 2. **Reversibility**： -Most software methods can be restored by reinstalling the system or resetting the configuration. -Physical isolation is the only solution that is close to “permanent”, but it may still be bypassed. --- ###**Conclusion** There is no absolute "permanent” and no hardware damage solution, but a combination of router restrictions, system policies, and physical isolation can achieve a highly reliable disable. It is recommended to give priority to **Reversible administrator-level control** and ensure the legality of the operation.