Understanding DHCP & DNS - Networking Basics

DHCP & DNS are the backbone of every modern network! Whether you're setting up a home network or learning cybersecurity, these two protocols make internet connectivity smooth and simple.

What is DHCP? ​

DHCP (Dynamic Host Configuration Protocol) automatically assigns network settings to devices when they connect. This means you don’t need to manually enter IP addresses for every device!

What DHCP Provides ​

• IP Address - Unique identifier for your device
• Subnet Mask - Defines your network range
• Default Gateway - Your path to the internet
• DNS Server Address - Points your device to websites

DHCP DORA Process ​

Discover - Client searches for a DHCP server
Offer - Server offers an available IP
Request - Client requests that IP
Acknowledge - Server confirms and assigns it

Technical Details ​

• Protocol: UDP
• Ports:
  • Server → 67
  • Client → 68

Tip: Without DHCP, you’d need to manually configure IPs for every device

---

​

What is DNS? ​

DNS (Domain Name System) works like the internet’s phonebook. It converts human-readable domain names into IP addresses so your browser can load websites.

What DNS Does ​

• Converts domain names like google.com
• Into IP addresses like 142.250.xxx.xxx

DNS Lookup Types ​

• Forward Lookup: Domain → IP
• Reverse Lookup: IP → Domain

Technical Details ​

• Protocol: UDP (mostly)
• Port: 53

Tip: Without DNS, you’d have to remember numbers instead of website names

---

​

Why DHCP + DNS Work Perfectly Together ​

DHCP assigns IPs automatically
DNS makes accessing websites easy
Together they provide:

• Fast connectivity
• Reliable communication
• User-friendly networking

---

​

Who Should Learn DHCP & DNS? ​

• IT Support Engineers
• Networking Students
• CCNA Aspirants
• Cybersecurity Enthusiasts

Example: Quick DHCP & DNS Check in Python ​

import socket

# DNS lookup example
hostname = 'google.com'
ip = socket.gethostbyname(hostname)
print(f"IP address of {hostname} is {ip}")

# Simple DHCP simulation (conceptual)
dhcp_info = {
    "IP Address": "192.168.1.10",
    "Subnet Mask": "255.255.255.0",
    "Gateway": "192.168.1.1",
    "DNS": "8.8.8.8"
}
print("DHCP Assigned Info:", dhcp_info)

This script shows how DNS resolves domains and how DHCP assigns network info in real life!