Blog | G5 Cyber Security

Block MAC Addresses on Your Network

G5 Cyber Security

TL;DR

Yes, you can block devices based on their MAC address, but it’s not foolproof and has limitations. This guide explains how to do it on your router and why it might not always work.

How to Block a MAC Address

  1. Find Your Router’s Login Page: Most routers use a web browser interface. Common addresses are 192.168.0.1 or 192.168.1.1. Check your router’s manual if you’re unsure.
    • Open a web browser and type the address into the bar.
    • You’ll be asked for a username and password. The default is often ‘admin’ for both, but check your router documentation.
  2. Locate MAC Address Filtering: Once logged in, look for settings related to:
    • MAC filtering
    • Access Control
    • Wireless Access Control (if blocking Wi-Fi devices)
    • Parental Controls (sometimes includes MAC address controls)
  3. Find the MAC Address to Block: You need the MAC address of the device you want to block. Here’s how to find it:
    • Windows: Open Command Prompt and type ipconfig /all. Look for ‘Physical Address’ under your network adapter (Ethernet or Wi-Fi).
    • macOS: Open System Preferences > Network, select your connection, click Advanced, then Hardware. The MAC address is listed as the ‘MAC Address’.
    • Android: Settings > About Phone > Status Information > Wi-Fi MAC address (location may vary).
    • iOS/iPadOS: Settings > General > About > Wi-Fi Address.
  4. Add the MAC Address to the Block List:
    • In your router’s settings, there will usually be a section to add MAC addresses.
    • Enter the MAC address carefully (it’s case-insensitive but must be accurate).
    • You may need to specify whether you are blocking or allowing this address. Choose ‘Block’.
  5. Save Your Changes: Click ‘Apply’, ‘Save’, or a similar button to save the new settings.
    • Your router might restart, so be patient.

Important Considerations

  1. MAC Address Spoofing: A tech-savvy user can change (spoof) their MAC address to bypass the block.
    • This is relatively easy to do, so it’s not a strong security measure.
  2. Static vs Dynamic IP Addresses: If the device uses a dynamic IP address (assigned automatically by your router), its MAC address might change when it reconnects.
    • Blocking based on IP address is more reliable in this case, but requires knowing the IP.
  3. Router Limitations: Some routers have limited block lists (e.g., only allow 32 MAC addresses).
  4. Wireless vs Wired: You may need to configure MAC filtering separately for your Wi-Fi network and any wired connections.
    • Look for separate sections in your router settings.
  5. Impact on Other Devices: Double-check the MAC address before blocking, as you could accidentally block a device you need to use.

Alternatives

For stronger security, consider these options:

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