A subnet segments a cloud network to isolate workloads for security and traffic management.Public subnets allow internet access; private subnets restrict it.Subnetting improves routing efficiency, enforces security and organizes cloud infrastructure.
What is Subnet?
A subnet, or subnetwork, is a logical subdivision of an IP network into two or more network segments. With subnets, large networks can be subdivided into smaller, more efficient subnetworks to meet connectivity and security requirements. The simplest subnet, a point-to-point subnet, connects two devices. A data center subnet connects many devices or groups of users, which can be in one or multiple locations.
A Class A, B, or C network can be subnetted. (There are five different classes of networks, A to E, but classes D and E are reserved.) The subnetting process allows the administrator to divide a Class A, Class B, or Class C network number into smaller portions. The subnets can be also be subnetted into sub-subnets.
Subnet masks define a range of IP addresses that can be used in a network and to designate subnetworks. A subnet mask makes it possible to identify which part of an IP address is reserved for the network and which part is available for host use. Like IP addresses, a subnet mask contains four bytes (32 bits) and is often written using the same, number/decimal format.
The subnet mask is used by the TCP/IP protocol to determine whether a host is on the local subnet or a remote network. With a local subnet, the device will send a request to retrieve the hardware address of the system to communicate over the data-link layer. For addresses on remote networks, devices route packets to the gateway for that network.
Subnets provide a number of benefits, including:
Reduce network congestion
Improve network performance
Maximize the number of permitted hosts on a network
Provide access to a network remotely without having to open the entire network
Enable point-to-point links or subnetworks to support a few devices
Enhance security by isolating segments of a network (e.g., finance, sales, legal)
Frequently Asked Questions
A subnet, or subnetwork, is a smaller segment of a larger network that helps organize and manage cloud resources more efficiently. Within a cloud environment, subnets divide a virtual network into separate sections, allowing administrators to group resources based on their purpose, security requirements, or workload type.For example, organizations often place web servers in a public subnet while keeping databases and internal applications in private subnets. This structure improves network management, enhances security, and helps control traffic flow between resources.
Subnets play a critical role in improving network performance, security, and scalability. By separating resources into different network segments, organizations can apply specific security policies, control access permissions, and reduce unnecessary traffic between workloads.Additionally, subnets make it easier to manage large cloud infrastructures. They help businesses organize resources efficiently, optimize IP address allocation, and support the deployment of applications across multiple availability zones or regions for greater reliability.
A public subnet contains resources that need direct access to the internet, such as web servers, load balancers, or public-facing applications. These resources typically have public IP addresses and are configured to accept incoming internet traffic.
A private subnet, on the other hand, is designed for resources that should not be directly accessible from the internet, such as databases, application servers, and internal services. Keeping sensitive resources in private subnets adds an extra layer of security by limiting external exposure while still allowing controlled communication within the cloud network.
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