Question 1

What is a subnet calculator?

Accepted Answer

A subnet calculator helps developers, DevOps engineers, and network administrators break down large IP networks into smaller, manageable subnets. It calculates important details like network addresses, subnet masks, and usable host ranges for both IPv4 and IPv6, making it easier to optimize network performance and manage IP address allocation. For DevOps teams, subnet calculators are especially useful when automating network configurations in cloud environments, managing scaling demands, and integrating with infrastructure as code (IaC) practices. By using one, you can streamline network design, reduce errors, and ensure that deployments follow best practices for network management.

Question 2

Table of typical subnets for IPv4?

Accepted Answer

Common IPv4 subnets include: /8 (255.0.0.0) with 16,777,214 usable hosts for very large networks; /16 (255.255.0.0) with 65,534 usable hosts for Class B medium networks; /24 (255.255.255.0) with 254 usable hosts for Class C small networks; /26 (255.255.255.192) with 62 usable hosts; /28 (255.255.255.240) with 14 usable hosts for very small subnets; and /30 (255.255.255.252) with 2 usable hosts for point-to-point links.

Question 3

What's the difference between IPv4 and IPv6?

Accepted Answer

IPv4 and IPv6 are two different versions of the Internet Protocol used to identify devices on a network, but they're quite distinct in what they offer. IPv4 uses 32-bit addresses, which gives us about 4.3 billion possible addresses. As more devices have come online, we've run out of those addresses, which is where IPv6 comes in. IPv6 uses 128-bit addresses, giving us a nearly limitless supply—enough to comfortably connect every device now and in the future. Beyond the bigger address space, IPv6 also brings improvements like more efficient routing, better support for new services like multicast, and built-in security features such as IPsec. IPv6 was designed to address IPv4's shortcomings, making it more future-proof with additional features that help improve both performance and security.

Question 4

What's the difference between IPv4 and IPv6 subnetting?

Accepted Answer

Subnetting in IPv4 and IPv6 serves a similar purpose—breaking up large networks into smaller parts—but it works differently because of how each version handles addresses. IPv4 addresses are limited, so subnetting is all about making the most of what you have. You take a 32-bit address and divide it into network and host portions using subnet masks (like /24 or /28). With IPv6, there's no need to worry about running out of addresses. You're working with 128-bit addresses, so the standard practice is to use /64 subnets, which provide an enormous number of IPs per subnet. IPv4 subnetting is about using a limited resource efficiently, while IPv6 subnetting is about creating a logical structure with plenty of room to grow.

Subnet Mask	CIDR Notation	Number of Hosts	Usable Hosts	Subnet Description
255.0.0.0	/8	16,777,216	16,777,214	Very large network
255.128.0.0	/9	8,388,608	8,388,606	Half of a /8 network
255.255.0.0	/16	65,536	65,534	Class B, medium network
255.255.128.0	/17	32,768	32,766	Half of a /16 network
255.255.255.0	/24	256	254	Class C, small network
255.255.255.128	/25	128	126	Half of a /24 network
255.255.255.192	/26	64	62	Quarter of a /24 network
255.255.255.224	/27	32	30	Smaller subnetwork
255.255.255.240	/28	16	14	Very small subnet
255.255.255.248	/29	8	6	Used for point-to-point
255.255.255.252	/30	4	2	Point-to-point links
255.255.255.254	/31	2	0	Used for router links

IPv4 subnet calculator.

Subnet calculator.

All 1 possible /24 networks with 256 IPs each for 192.168.255.*.

How to use the IPv4 subnet calculator?

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Frequently Asked Questions.

What is a subnet calculator?

Table of typical subnets for IPv4?

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IPv4 subnet calculator.

Subnet calculator.

All 1 possible /24 networks with 256 IPs each for 192.168.255.*.

How to use the IPv4 subnet calculator?

Get 50 monitors with 5-minute checks totally FREE.

Frequently Asked Questions.

What is a subnet calculator?

Table of typical subnets for IPv4?

Get your FREE account now, 50 monitors included!

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