00:00Ever wondered if someone is secretly using your Wi-Fi?
00:03Unauthorized devices on your network can slow down your internet
00:06and more importantly, they pose a significant security risk.
00:10Today, I am going to show you a powerful technique to detect these.
00:15Freeloaders using a tool already built into your Windows computer.
00:18No special software needed, just a few simple commands.
00:21By the end of this video, you'll be able to scan your network like a pro
00:25and take control of your digital security.
00:27Let's dive in and secure your connection.
00:30First, we need to open the command prompt.
00:33It might sound technical, but it's incredibly simple.
00:36Go to your start menu, type CMD, and you'll see command prompt appear.
00:40Right-click on it and select Run as Administrator.
00:43This gives us the necessary permissions to perform network diagnostics.
00:47A black window will pop up.
00:49This is our command center for today's task.
00:52Running as an administrator ensures that the commands we use
00:55will have full access to the network information we need,
00:58giving us the most accurate results possible.
01:01Now that we have the command prompt open,
01:03we're going to use a simple yet powerful command.
01:06Type ARP, a RP, followed by a space, a hyphen, and the letter A.
01:12So it looks like this, ARP A, then press Enter.
01:17What you're seeing now is the ARP table for your network.
01:20ARP stands for Address Resolution Protocol,
01:23and its job is to map IP addresses to physical MAC addresses on your local network.
01:28This list effectively shows every device that your computer has recently communicated with on your Wi-Fi.
01:34Let's break down what this output means.
01:36You'll see several columns.
01:37The first column, Internet Address, shows the IP address of a device.
01:42The second, Physical Address, is the MAC address,
01:46which is a unique hardware identifier for every network-capable device.
01:50The third column, Type, tells you if the entry is dynamic or static.
01:55Dynamic entries are learned automatically as devices communicate,
01:59which is what we're interested in.
02:00Static entries are manually configured.
02:03Each line represents a single device on your network.
02:06So, how do we know which devices are yours and which might be intruders?
02:11The key is to identify the MAC addresses of your own devices.
02:15Let's start with your Windows PC.
02:16In the same command prompt window, type ipconfig ipc onfig g a space a forward slash and then all.
02:24So, ipconfig per all.
02:25Press Enter.
02:27Scroll through the information until you find your Wi-Fi adapter.
02:30The physical address listed there is your computer's MAC address.
02:34Make a note of it.
02:36Next, let's find the MAC address for your smartphone.
02:39For an iPhone, go to Settings, then General, then About.
02:43Scroll down and you'll find the Wi-Fi address that's your MAC address.
02:47On an Android phone, this may vary slightly by manufacturer,
02:50but you'll typically find it under Settings, then About Phone, then Status, or under Wi-Fi and Network Settings.
02:58Look for an entry labeled Wi-Fi MAC address.
03:01Again, write this down.
03:03Repeat this process for all your trusted devices.
03:06Your tablets, smart TVs, gaming consoles, and any other smart home gadgets connected to your network.
03:11Now comes the detective work.
03:14Go back to your command prompt window with the ARP A list.
03:18Take the list of MAC addresses you just collected from your trusted devices and start cross-referencing.
03:23Go down the Physical Address column in the Command Prompt output.
03:27For each entry, check if it matches one of the make addresses on your list of known devices.
03:32Your router will also be on this list, usually associated with an IP address ending in 1 or 254.
03:41If you see a MAC address in the ARP table that you can't account for, you may have found an
03:46unauthorized device.
03:47So you found a suspicious MAC address, what's next? Don't panic.
03:51The first and most important step is to change your Wi-Fi password immediately.
03:56Log into your router's administration page, navigate to the Wireless Security Settings,
04:00and create a new strong password.
04:03Use a combination of upper and lowercase letters, numbers, and symbols.
04:07This will kick all connected devices off your network, forcing them to re-enter the new password to reconnect.
04:14This single action is often enough to block an unauthorized user.
04:18For an even higher level of security, you can enable MAC address filtering on your router.
04:24This feature allows you to create a whitelist of approved devices.
04:27Once you enable it, you'll enter the MAC addresses of all your trusted devices into the router's settings.
04:34With MAC filtering active, only the devices on your whitelist will be able to connect to your Wi-Fi.
04:39Even if someone knows your password.
04:41It's like having a bouncer for your network, checking an exclusive guest list at the door.
04:46To wrap things up, regularly checking your network for unauthorized devices is a great security habit.
04:52Using the ARP-A command is a quick and effective way to do this.
04:57Remember the key steps.
04:58Run ARP-A in an administrator command prompt.
05:01Collect the MAC addresses of all your trusted devices, and compare the two lists.
05:06If you find an intruder, immediately change your Wi-Fi password to a strong one,
05:11and consider enabling a MAC filtering for an extra layer of defense.
05:15Proactive monitoring is the foundation of good cybersecurity.
05:18Thank you for watching.
05:20By taking these simple steps, you've made your home network significantly more secure.
05:24If you found this guide helpful, please give it a thumbs up,
05:28and consider subscribing for more cybersecurity tips and tutorials.
05:32Stay safe online, and I'll see you in the next video.
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