What is Subnet?
Turkish: Alt Ağ (Subnet)
A subnet divides an IP address range into smaller network sections for routing, security boundaries, and address management.
What is Subnet?
A subnet is a smaller, manageable section of a larger IP network. For example, 10.0.1.0/24 is CIDR notation that describes both an address range and how much of each address is interpreted as the network portion.
Subnet design combines address ranges, default gateways, route tables, broadcast domains, and security rules. In IPv4 networks, private address ranges and NAT are common. IPv6 provides a much larger address space, but segmentation and routing plans still matter.
Why It Matters
Subnets are used to separate departments in an office network, application tiers in a data center, and public or private resources in the cloud. A common cloud pattern is to place web servers in a public subnet while keeping databases in private subnets that only the application layer can reach.
A good subnet plan leaves room for growth, avoids overlapping IP ranges, and provides a foundation for network segmentation. Poor planning can cause VPN conflicts, routing confusion, or overly broad security rules. Subnet count, address capacity, and access policy should therefore be designed together at the start of an infrastructure project.
Related Terms
An IP address is a numeric label used to identify devices on a network and route data packets to the correct destination.
NAT (Network Address Translation)NAT translates private network addresses to public addresses or ports, allowing local devices to communicate across the internet.
Network SegmentationNetwork segmentation separates users, servers, and systems into controlled network zones to limit unauthorized access and attack spread.
VLANA VLAN separates devices into logical network groups on shared hardware, isolating traffic and tightening access control.