What do subnet masks mean

Class A is for networks with more than 65, hosts. A Class B subnet mask claims the first two octets for the network, leaving the remaining part of the address, the 16 bits of octets 3 and 4, for the subnet and host part. Class B is for networks with to 65, hosts. In a Class C subnet mask, the network portion is the first three octets with the hosts and subnets in just the remaining 8 bits of octet 4. Class C is for smaller networks with fewer than hosts. You can determine the number and type of IP addresses any given local network requires based on its default subnet mask.

Subnetting is the technique for logically partitioning a single physical network into multiple smaller sub-networks or subnets. Subnetting enables an organization to conceal network complexity and reduce network traffic by adding subnets without a new network number. When a single network number must be used across many segments of a local area network LAN , subnetting is essential. This is the sole standards-based format in IPv6 to denote routing or network prefixes.

To assign an IP address to a network interface since the advent of CIDR, there are two parameters: a subnet mask and the address. Some know how to calculate subnet masks by hand, but most use subnet mask calculators. Incorrect Default Gateway: A computer configured with an incorrect default gateway can communicate with hosts on its own network segment. But it will fail to communicate with hosts on some or all remote networks.

A host can communicate with some remote networks but not others if the following conditions are true:. Internet--The global collection of networks that are connected together and share a common range of IP addresses.

Network--There are two uses of the term network in this article. One is a group of computers on a single physical network segment. The other is an IP network address range that is allocated by a system administrator. Octet--An 8-bit number, 4 of which comprise a bit IP address. They have a range of that correspond to the decimal values Wide area network WAN --A large network that is a collection of smaller networks separated by routers.

The Internet is an example of a large WAN. Feedback will be sent to Microsoft: By pressing the submit button, your feedback will be used to improve Microsoft products and services. Privacy policy. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info.

Contents Exit focus mode. Lining up the IP address and the subnet mask together, the network, and host portions of the address can be separated: It gives you the following addresses: Some other common subnet masks are: Decimal Binary Following are the ranges of Class A, B, and C Internet addresses, each with an example address: Class A networks use a default subnet mask of In some scenarios, the default subnet mask values don't fit the organization needs for one of the following reasons: The physical topology of the network The numbers of networks or hosts don't fit within the default subnet mask restrictions.

The next section explains how networks can be divided using subnet masks. These four networks would have as valid host addresses: A host can communicate with some remote networks but not others if the following conditions are true: A single physical network has more than one router. The wrong router is configured as a default gateway. Glossary Broadcast address--An IP address with a host portion that is all ones.

Network address--An IP address with a host portion that is all zeros. Router--A device that passes network traffic between different IP networks.

Subnet Mask--A bit number used to distinguish the network and host portions of an IP address. Subscribe to the daily or weekly newsletter and get featured terms and quizzes delivered to your inbox. You can unsubscribe or change your frequency setting at any time using the links available in each email. Please contact us. We just sent you an email to confirm your email address. Once you confirm your address, you will begin to receive the newsletter.

Subnet Mask. A subnet mask of Definitions by TechTerms. Tech Factor? Machine intelligence is an umbrella term that's used to describe the accuracy of a machine learning ML , deep learning DL or classical algorithm output. In business-to-business B2B marketing, the term is also being used to describe a growing market segment for information technology IT View Full Term. By clicking sign up, you agree to receive emails from Techopedia and agree to our Terms of Use and Privacy Policy.

A subnet mask is a bit number used to differentiate the network component of an IP address by dividing the IP address into a network address and host address. It does so with bit arithmetic whereby a network address is bit multiplied by the subnet mask reveal the underlying subnetwork.

Like the IP address, a subnet mask is written using the "dotted-decimal" notation. Subnet masks are used to design subnetworks, or subnets, that connect local networks. It determines both the number and size of subnets where the size of a subnet is the number of hosts that can be addressed.