Lecture Notes: DHCP for IPv4 and IPv6

Introduction to DHCP

• DHCP stands for Dynamic Host Configuration Protocol.
• Allows automatic assignment of IP addresses to clients.
• Essential for large networks to avoid manual configuration.
• Prevents IP address conflicts by central management.

Benefits of DHCP

• Centralized IP Management: Administers IP addresses from a centralized DHCP server.
• Scalability: Suitable for large networks like LANs with many devices.
• Additional Configurations: Can assign subnet mask, default gateway (router), and DNS information.
• Ease of Administration: Reduces effort for network administrators as they don’t need to configure IPs manually on each device.
• Dynamic Assignment: Automatically assigns IP addresses to devices, which is ideal for client machines in a LAN.

Scenarios Not Recommended for DHCP

• Static IP Requirement: Not suitable for devices requiring constant IPs (Routers, Firewalls, Servers).
• Manual IP Assignment: Use for special devices where IP consistency is crucial.
• IP Binding: Although binding IPs to MAC addresses is possible, some devices are better off with static IPs.

DHCP Process: DORA

• DORA steps:
  • Discover: Client sends a broadcast request to find a DHCP server.
  • Offer: DHCP server offers an IP address to the client.
  • Request: Client requests the offered IP address.
  • Acknowledge: DHCP server acknowledges and assigns the IP address to the client.

Practical Implementation

• DHCP Server Setup: Can be on any server OS (Linux, Microsoft) or a configured router.
• How DHCP Works:
  • Client boots and sends a DISCOVER message (broadcast) to find a DHCP server (255.255.255.255:67).
  • DHCP server responds with an OFFER message containing an IP address.
  • Client requests the offered IP address through a REQUEST message.
  • DHCP server acknowledges the request and assigns the IP address through an ACK message.

Conclusion

• Obtain IP Automatically: Configuring clients to obtain IP addresses automatically ensures they receive IPs from DHCP server seamlessly.
• Future Sections: Practical demonstration on setting up a router as a DHCP server and verifying the process.