Domain Name System (DNS) is a technique that involves naming network systems and computers so that you can easily find, track, and work with them. Checking your computer's DNS settings can be useful if you want to find out specific information about DNS on your network (for example, the IP address of a domain or server).
Steps
Method 1 of 6: Checking DNS Settings on Windows

Step 1. Swipe down from the right side of your Windows 8 device to access the Start screen
If you are using a mouse, hover over the lower left corner to access the start screen

Step 2. Enter "Control Panel" in the search bar and select it from the search results

Step 3. In the "Network and Internet" section, select "View network status and tasks."
A list of all active networks will be displayed.

Step 4. Click on the link located to the right of the "Connections" label for the network whose DNS settings you want to know
The network status window will open.

Step 5. Click on the "Properties" button

Step 6. Click on “Internet Protocol Version 4 (TCP / IPv4).”

Step 7. Click on the "Properties" button
The current DNS settings are displayed at the bottom of the Properties window.
Method 2 of 6: Checking DNS Settings in Windows 7 / Vista

Step 1. Click on the "Start" button and select "Control Panel"

Step 2. In the box in the upper right corner of the control panel, enter “Network and Sharing”

Step 3. In the search results, select “Network and Sharing Center”

Step 4. In the left part of the window, click on "Change adapter settings"

Step 5. Right click on the network whose DNS settings you want to check

Step 6. Select “Properties” from the list of options

Step 7. Click on “Internet Protocol Version 4 (TCP / IPv4).”

Step 8. Click the "Properties" button
Your DNS settings will be at the bottom of the window next to the DNS server fields
Method 3 of 6: Checking DNS Settings in Windows XP

Step 1. Click on the "Start" button

Step 2. Select “Control Panel”

Step 3. Click on “Network Connections”
The "Network Connections" window will open.

Step 4. Right click on “Local Area Connection” and select “Properties”
If you are connected to a Wi-Fi network, right-click on “Wireless Network Connection” and select “Properties”

Step 5. Select “Internet Protocol (TCP / IP)”

Step 6. Click the "Properties" button
Your DNS settings will be at the bottom of the Properties window, next to the DNS server fields.
Method 4 of 6: Checking DNS Settings on Mac OS X

Step 1. Click on the Apple icon at the top of your Mac desktop

Step 2. Select “System Preferences”

Step 3. In the system settings, click on the "Network" icon

Step 4. In the left part of the window, select the required network whose DNS settings you want to find out

Step 5. Click on the "Advanced" button

Step 6. Select the “DNS” tab
The current DNS settings will be displayed in the “DNS Server” and “Search Domains” fields.
Method 5 of 6: Checking DNS Settings in Ubuntu

Step 1. Click on the network icon in the upper left corner of your Ubuntu desktop
It will look like two arrows or a Wi-Fi symbol.

Step 2. Click on “Change connections”
A window with network connections will open.

Step 3. Click on the name of the network whose DNS settings you want to know

Step 4. Click on the "Parameters" button located in the lower right corner of the window

Step 5. Click on the “IPv4 Settings” tab

Step 6. The information you need is in the “DNS Servers” field
These are the current DNS settings of your computer.
Method 6 of 6: Checking DNS Settings on Fedora

Step 1. On the Fedora desktop, click on the network icon
It shows two computers.

Step 2. In the options select “Edit Connections”
The network connections window will open.

Step 3. Select the name of the network whose DNS settings you want to check

Step 4. Click on the “Edit” button

Step 5. Click on the “IPv4 Settings” tab
The current DNS settings will be in the “DNS Servers” field.