🌐 What is a Subnet Mask?

📖 Definition
A subnet mask is a 32-bit number used to divide an IP address into network and host portions.

🧠 Concept

1 → Network

0 → Host

📍 Example:
IP: 192.168.1.10
Mask: 255.255.255.0

👉 Network = 192.168.1
👉 Host = 10

🧠 CIDR (Classless Inter-Domain Routing)

📖 Definition
CIDR is a notation that represents the number of network bits in an IP address.

📍 Example:
192.168.1.0/24

🔄 Subnet Mask vs CIDR

⚡ Why is Subnetting Important?

Efficient IP usage

Better network segmentation

Improved performance & security

🎯 Interview Focus (Very Important)

❓ What is subnet mask?
A subnet mask is used to separate the network portion and host portion of an IP address, enabling efficient routing and network segmentation.

❓ What is CIDR?
CIDR is a method of representing IP addresses using slash notation to define the number of network bits.

❓ Difference between subnet mask and CIDR?
Subnet mask is written in dotted decimal format, while CIDR is a compact representation using slash notation.

❓ What is /24?
/24 means the first 24 bits are used for the network and the remaining 8 bits are used for hosts.