What Is A Subnet Mask Used For

I'm sure that you have heard the word subnet before. It is often in error messages or when talking about networks. For us techy people, it'southward clear as day what a subnet is, and we can nigh likely tell yous how many devices a network can have (in that location is always a limit), based on the subnet mask.

Only yous don't care about that. You want to know what is and how you lot tin find yours and for that, you have clicked on the right article. In this commodity, we volition explicate what a subnet mask is, why it is so important and the difference between subnet masks and IP addresses as well as how you can calculate a subnet mask and how you can find your subnet mask.

What is a Subnet Mask?

In order to understand what a subnet mask is you beginning demand to know what an IP (Cyberspace Protocol) address is. Every device that connects to a network needs its own unique IP address if you are using Internet protocol to allow the devices to communicate with each other. An IP address is a string of numbers separated by full stops for example:

172.16.81.100

A subnet mask is again a number and what it does is ascertain a range of IP addresses that a network tin can employ. Subnet is short for sub-networks and these are normally local networks that connect to the Internet. A subnet mask will designate these sub-networks.

Devices that are located on the aforementioned sub-network can communicate with each other. If devices on some other subnetwork desire to communicate with devices on a different subnetwork then they will require a router to road the commutation betwixt the sub-networks. You can use a subnetwork to division numerous networks and therefore limit the advice betwixt them.

The task of a subnet mask is to hide the network element of an IP address. Only the host chemical element is visible. We will explain what a Class C IP address is in more detail subsequently, just one of the most common Course C subnet masks is 255.255.255.0

Like an IP accost, each department of the subnet mask address can contain any numbers from 0 to 255. For the subnet mask 255.255.255.0, the first 3 sections are full which means that device IP addresses within this subnet mask must exist the aforementioned as the initial iii sections. The last section tin be whatsoever number betwixt 0 and 255.

An example best explains this. The two IP addresses 12.0.1.101 and 12.0.1.102 are located on the same subnet but the IP address 12.0.2.101 would be on a different subnet. With a subnet mask of 255.255.255.0, there is 256 IP address but but 254 of these can exist used for hosts. This is because the gateway (usually the first accost) and the circulate address (usually the terminal address) is reserved.

Why is a Subnet So Of import?

1 of the most of import reasons for a subnet is security. When you are on the same subnet as other devices at that place is complimentary communication but devices on other subnets volition not be able to access your subnet.

A good example of this is your dwelling network. In your network, you accept a router that will utilize subnet for security. Your Internet service provider will allocate a public IP to y'all. This IP address is what all the websites and anything that you connect to volition run into. However, if you bank check your reckoner'southward IP accost, information technology will most probable be some other IP then the public one.

This is because there is a subnet on the home side of your router that cannot exist routed to from the outside. What needs to happen, is that traffic coming in needs to go through the router that then translates and routes the traffic to the correct device. This way, everything is however continued, while nonetheless not being direct continued.

A subnet will increment the number of devices that tin access the Internet. With standard IPv4 networking, there are only effectually three billion IP addresses bachelor. This is nowhere about plenty to meet the global demand for device connection.

And so, a subnet is used to enable a collection of devices to connect to the Internet with a unmarried IP address through the apply of a router (like you have at home or in your office) and in this way a lot more than than 3 billion devices can have admission to the Cyberspace. This is what was explained above with one public address for your whole network.

A typical subnet mask for habitation networks is 255.255.255.0. This is a 24-bit mask and allows up to 256 IP addresses. However, "simply" 254 hosts are possible, which should exist enough for nearly homes.

Simply business that has thousands of devices, 254 is no skillful at all. The good thing is that 255.255.255.0 can exist inverse to something else, thus increasing the network and the capacity of hosts. For instance, 255.255.0.0, which is a 16-bit mask, tin can take 65 536 hosts. If you desire to know more about sizes, I recommend checking out this cheat canvass on Aelius.com.

What is the Difference Betwixt an IP Address and a Subnet Mask?

So, this might exist a bit disruptive. How to know the divergence betwixt a subnet mask and an IP? Permit's use an example to clear out the confusion.

The best way to do this is to think of an IP address similar a home address or the physical accost of your concern. And then, let's say that one of your friends wants to transport you a letter. They will add your address to the envelope and so add together a stamp and put into their local mailbox.

The postal worker will remember the letter of the alphabet and if the address is local then they volition mail service it directly into your mailbox. If the address is in some other state, metropolis or town so it will go to the central mail office where workers will sort it and dispatch it to where information technology needs to become. An IP address works in a similar way.

So, if your IP accost is 20.0.0.1 and your subnet mask is 255.0.0.0 this means that addresses in the 20.x.x.x range are in your local network like addresses in your local surface area. However, if y'all want to send something to an IP address outside of your subnet such as 30.0.0.1 so you cannot do this directly (they volition exist in a unlike state, city or town).

In this case, the postal service has to go to the local central office and then dispatched to the local cardinal office of the intended recipient. The postal worker tin then deliver it.

So an IP address is a number that has a network number, a subnetwork number (this is optional) and a host number. Both the network and subnetwork numbers are used in routing and the host number is the host address.

A subnet mask defines the format of an IP accost numerically where the network and subnetwork bits that form the address accept mask bit values of 1 and the host component of the address uses a mask bit value of 0.

What is Class A, Grade B, and Class C Networks?

The InterNIC provides all public Internet addresses as information technology is responsible for administering everything. It divides IP addresses into separate classes and the most mutual classes are Form A, Class B, and Class C addresses.

Each of these classes uses a different subnet mask by default and you can easily identify the course of an IP address past the first octet that it uses.

Class A Addresses

In a Course A network, you would see the default subnet mask of 255.0.0.0 used. This means that the first octet of Class A IP addresses would exist between 0 and 127. An example Course A IP accost would be 12.48.24.9

Course A networks take an 8-flake prefix with the highest bit set to 0. There is a 7-bit network number and the host number is 24 bit. With Class A there is a maximum of 126 networks.

Class B Addresses

In a Class B network, you lot would encounter the default subnet mask of 255.255.0.0 used. This means that the outset octet of Class B IP addresses would be between 128 and 191. An example Class B IP address would be 171.17.51.64

Class B networks have a 16-bit prefix with the highest fleck order set to 1-0. The network number is 14 flake and the host number is 16 bit.

Class C Addresses

In a Class C network, yous would come across the default subnet mask of 255.255.255.0 used. This means that the first octet of Form C IP addresses would be between 192 and 223. An example Class C IP accost would be 194.166.124.133

Course C networks take a 24-bit prefix with the highest fleck lodge set up to 1-1-0. The network number is 24 flake and the host number is 8 flake.

How to Detect Your Subnet Mask

This will be dissimilar depending on if you lot are using a Windows, Mac or Linux.

For Windows 10:

Open Command Prompt by searching for CMD
Type ipconfig and press enter
At that place will be a line named "Subnet Mask" which tells you your computers subnet mask

For Mac and Linux users: