DHCP
Created: 2025-11-25 Tags: networking dhcp protocols ip-addressing
Description
DHCP (Dynamic Host Configuration Protocol) automatically assigns IP addresses and network configuration to devices on a network.
Key Concepts
DORA Process
- Discover: Client broadcasts for DHCP server
- Offer: Server offers IP configuration
- Request: Client requests offered configuration
- Acknowledge: Server acknowledges assignment
DHCP Components
- DHCP Server: Assigns addresses
- DHCP Client: Requests configuration
- Scope: Range of available IPs
- Lease: Time period for IP assignment
- Reservations: Static IP for specific MAC
Information Provided
- IP address
- Subnet mask
- Default gateway
- DNS servers
- Domain name
- Lease duration
Security Considerations
Attacks
- Rogue DHCP Server: Attacker provides malicious configuration
- DHCP Starvation: Exhaust IP pool
- DHCP Spoofing: Impersonate DHCP server
Protections
- DHCP Snooping on switches
- Port security
- IP Source Guard
- Monitor for rogue DHCP servers
- Static IP for critical infrastructure
Related Topics
Back to: 00-MOC-Cybersecurity-Roadmap