Calculateur de Sous-réseau
Calculez les masques de sous-réseau, la diffusion et la plage d'utilisation
What is a Subnet Calculator?
A Subnet Calculator is an essential tool for network administrators and IT engineers. It allows for the division of an IP network into smaller, more manageable sub-networks, optimizing address usage and improving infrastructure security and performance.
Understanding CIDR and Subnet Masks
The CIDR (Classless Inter-Domain Routing) system replaced the old classful system (A, B, C) with a more flexible way of allocating IP addresses. By using a prefix (like /24), you define how many bits are used for the network and how many remain for the hosts.
What this tool calculates:
- Network Address: The first address in the subnet, used for identification.
- Broadcast Address: The last address, used for communicating with all devices on that network.
- Usable Hosts: The actual number of devices you can connect (always 2 less than the total).
- Subnet Mask: The decimal representation (e.g., 255.255.255.0) of the CIDR prefix.
Why IT Professionals use it
Mastering network segmentation is vital for configuring VLANs, routers, and firewalls. Using a reliable calculator prevents manual binary calculation errors that could lead to IP conflicts and service downtime.