Class A IP Analysis

Nerd Cafe | نرد کافه

Let’s do a step-by-step IP analysis of:

IP: 10.20.30.40/8

We will find:

1. Network IP

2. Broadcast IP

3. First IP (usable)

4. Last IP (usable)

5. Number of available IPs (hosts)

6. Subnet mask

Write IP in binary

Break down each octet to binary:

Octet	Decimal	Binary
1	10	00001010
2	20	00010100
3	30	00011110
4	40	00101000

Full IP in binary:

00001010.00010100.00011110.00101000

1. Subnet Mask in binary

CIDR = /8

Means:

• 8 bits for network (all 1’s)

• 24 bits for host (all 0’s)

Octet	Decimal	Binary
1	255	11111111
2	0	00000000
3	0	00000000
4	0	00000000

Subnet mask:

255.0.0.0

Binary:

11111111.00000000.00000000.00000000

Meaning:

• First 8 bits = Network part

• Last 24 bits = Host part

2. Find Network Address

Rule:

Network Address = IP AND Subnet Mask

IP in binary:

00001010.00010100.00011110.00101000

Subnet Mask:

11111111.00000000.00000000.00000000

Bitwise AND:

00001010.00000000.00000000.00000000

Convert to decimal:

Octet	Binary	Decimal
1	00001010	10
2	00000000	0
3	00000000	0
4	00000000	0

Network Address

10.0.0.0

3. Find Broadcast Address

Rule:

Broadcast = Network Address with all host bits = 1

• Network bits (first 24) stay the same

• Host bits (last 8) all 1

Binary:

00001010.11111111.11111111.11111111

Decimal:

Octet	Binary	Decimal
1	00001010	10
2	11111111	255
3	11111111	255
4	11111111	255

Broadcast Address

10.255.255.255

4. First Usable IP

Rule:

First Usable = Network Address + 1

• Network Address: 10.0.0.0

• Add 1 to last octet:

Network Address:

10.0.0.0

First IP in Binary:

00001010.00000000.00000000.00000001

First Usable IP

10.0.0.1

5. Last Usable IP

Rule:

Last Usable = Broadcast - 1

• Broadcast Address: 10.255.255.255

• Subtract 1 from last octet:

Broadcast Address:

10.255.255.255

Last IP in Binary:

00001010.11111111.11111111.11111110

Last Usable IP

10.255.255.254

6. Number of Usable IPs

Rule:

$$Usable\;IPs=2^{host\;bits}-2$$

• Host bits = 24 (since /24)

• Calculation:

2^24 = 16,777,216
16,777,216 - 2 = 16,777,214

Number of usable IP

16,777,214

Final Answer in Table (with Binary)

Item	Decimal	Binary
Subnet Mask	255.0.0.0 (/8)	11111111.00000000.00000000.00000000
Network Address	10.0.0.0	00001010.00000000.00000000.00000000
Broadcast Address	10.255.255.255	00001010.11111111.11111111.11111111
First Usable IP	10.0.0.1	00001010.00000000.00000000.00000001
Last Usable IP	10.255.255.254	00001010.11111111.11111111.11111110
Number of Usable IPs	16,777,214	(2^16)-2

💖 Support Our Work

If you find this post helpful and would like to support my work, you can send a donation via TRC-20 (USDT). Your contributions help us keep creating and sharing more valuable content.

TRC-20 Address: TAAVVf9ZxUpbyvTa6Gd5SGPmctBdy4PQwf

Thank you for your generosity! 🙏

Keywords

Network IP , Broadcast IP , First IP (usable) , Last IP (usable) , Number of available IPs (hosts) , Subnet mask , Nerd Cafe , نرد کافه

Channel Overview

🌐 Website: www.nerd-cafe.ir

📺 YouTube: @nerd-cafe

🎥 Aparat: nerd_cafe

📌 Pinterest: nerd_cafe

📱 Telegram: @nerd_cafe

📝 Blog: Nerd Café on Virgool

💻 GitHub: nerd-cafe