The network is divided into subnets so that data can be moved more quickly, as well as easier to manage. Routers do this by dividing the subnet mask, which is a number indicating where to look for the IP address that defines the subnetwork. In most cases, finding the subnet mask on your computer is easy. For some other devices, this is more difficult to do. If you are required to enter a subnet mask, you can use the same subnet mask as the computer.
Step
Method 1 of 4: Finding Subnet Mask in Windows
Step 1. Open Command Prompt
Press the Windows key, then press R to open a Command Prompt window.
- If that doesn't work, click the start button or the Windows logo in the lower-left corner of the screen. Type "command prompt" into the search bar, then double-click on the icon that appears. You may need to press Search to access the search bar.
- If there's no icon in the lower left corner, hover your mouse over the lower right corner and move it up, or swipe from right to left if you're using a touch screen.
Step 2. Enter the ipconfig command
Type command ipconfig /all, and make sure that you enter them exactly, with a space separating the two words in the command. Press the Enter key. Windows ipconfig is a program that monitors all your network connections. The command will display a list of all your networks information.
Step 3. Find the subnet mask
The subnet mask is in the section titled "Ethernet adapter Local Area Connection". Find the line starting with "Subnet Mask", then look at the information next to it to find the subnet mask. Most subnet mask numbers start with some 255, for example 255.255.255.0.
Step 4. As another option, find the subnet mask via Control Panel
Here's another way to find information about the subnet mask:
- Go to Control Panel → Network & Internet → Network and Sharing Center.
- On most modern Windows systems, click "Change adapter settings" on the left. For Windows Vista, click "Manage Network Connections".
- Right click on ' Local Area Connection ", then select " Status ". Click " Details " in the window that opens. Look for your subnet mask.
Method 2 of 4: Finding Subnet Mask on Mac
Step 1. Click the "System Preferences" icon on your Mac's dock
If the icon isn't in the dock, click the Apple logo in the upper-left corner of the screen, then select "System Preferences".
Step 2. Click the "Network" icon
In the "System Preferences" window, the Network icon looks like a gray ball on most versions of Mac OS X. If you can't find it, type "Network" into the search bar in the upper-right corner of the System Preferences window.
Step 3. Select your internet connection from the list shown on the left
Click the network name that has a green dot next to it, as well as the word "Connected" below it.
Step 4. Click "Advanced" if you are using Wi-Fi
The options are at the bottom right. On most types of network connections, you can see the Subnet Mask written on the right side of the screen.
Step 5. Select the TCP/IP tab in the "Advanced" window
TCP/IP on Mac determines how communication accesses the network.
Step 6. Find the subnet mask
The subnet mask will be written with the proper label, and the number will start with 255.
If the number you see is halfway down the screen, under "Configure IPv6", it means you're on an IPv6-only network, which doesn't use a subnet mask. If you must connect online, try selecting "Using DHCP" from the "Configure IPv4" drop-down menu, then pressing Renew DHCP Lease
Method 3 of 4: Finding Subnet Masks on Linux
Step 1. Open Command Line
If you don't know how, you'll need to do an internet search on how to open it for the version of Linux you're using.
Step 2. Enter the ifconfig command
In the Command Line window, type ifconfig, then press Enter.
If all you see is a message saying you need root (administrator) access, you'll need to get administrator access first
Step 3. Find the subnet mask
The subnet mask will be labeled "Mask" or "Subnet Mask". The subnet mask number will start with 255.
Method 4 of 4: Setting Subnet Mask on TV and Other Devices
Step 1. Use the same subnet mask as the computer
When setting up a smart TV or other device, you may be asked to enter a subnet mask. The subnet mask number only applies to the local network being used. For best results, follow the guide above to find the subnet mask on your computer. The subnet mask number obtained should work on the device as well.
- If the device still cannot connect to the internet, leave the subnet mask information exposed on the computer. Make sure that you change the subnet mask setting on the device while viewing the information on the computer.
- If you cannot find the subnet mask information on the computer, try entering 255.255.255.0. 255.255.255.0 is the most common subnet mask for home networks.
Step 2. Change the IP address
If the device still cannot connect to the internet, check the IP address of the device. The IP address should be displayed on the same screen as the subnet mask. Compare the device's IP address with the computer's IP address, which should also be found with the computer's subnet mask. Copy the IP address of the computer, except for the last digits or the number after the last period. Choose a larger number, as long as the number is still equal to 254 or less. Add the last digit of the computer's IP address by 10 or more, as close numbers may already be used by other devices on the same network.
- For example, if the computer's IP address is 192.168.1.3, set the device's IP address to 192.168.1.100
- If you can't find your computer's IP address, find the label affixed to the router, or do an online search with the router brand keyword and the word "IP address".
- If you can't find any information, try 192.168.1.100, 192.168.0.100, 192.168.10.100, or 192.168.2.100.
Step 3. Enter the Gateway address
The Gateway address must be the same as the one used on the computer, which is also the router's IP address. The Gateway address should always be nearly the same as the device's IP address, but the group of numbers in the last digit is always 1.
- For example, if a device connected to the network has an IP address of 192.168.1.3, enter 192.168.1.1 as the Gateway address.
- With any browser, type http:, then follow with Gateway address. If correct, router information will be displayed.
Step 4. Specify DNS
Use the same DNS settings as the computer, or the same values, as entered under Gateway addresses. Alternatively, do a search with the keyword "public DNS" for more options.
Step 5. Contact the device manufacturer
If the device still cannot connect to the network after setting up, contact the device manufacturer's technical service department.
Tips
- If the subnet mask value is 0.0.0.0, you may not be connected to an active internet connection.
- The subnet mask will appear on the active adapter. For example, if you use a wireless signal receiving card to connect a computer to the network, the subnet mask will appear on the card's information. If you have more than one adapter, such as a wireless card and a wired network card, you may have to scroll through the screen until you find the active subnet mask information field.
- IPv6-only networks do not use a subnet mask. The subnet ID is concatenated with the IP address in IPv6. A colon-separated fourth group of address digits defines your subnet address (or the 49th through 64th binary digits).
