DHCP Addressing Overview

Question 1

DHCP

Answer 1

• IP address configuration used to be manual
• IP address, subnet mask, gateway, DNS servers, NTP
servers, etc.

• October 1993 - The bootstrap protocol - BOOTP

• BOOTP didn’t automatically define everything
• Some manual configurations were still required
• BOOTP also didn’t know when an IP address might
be available again

• Dynamic Host Configuration Protocol
  
  • Initially released in 1997
  • Updated through the years

Question 2

DHCP process

Answer 2

• Step 1: Discover - Client to DHCP Server
  
  • Find all of the available DHCP Servers
• Step 2: Offer - DHCP Server to client
  
  • Send some IP address options to the client
• Step 3: Request - Client to DHCP Server
  
  • Client chooses an offer and makes a formal request
• Step 4: Acknowledgment - DHCP Server to client
  
  • DHCP server sends an acknowledgment to the client

Question 3

Managing DHCP in the enterprise

Answer 3

• Limited Communication range
  
  • Uses the IPv4 broadcast domain
  • Stops at a router
• Multiple servers needed for redundancy
  
  • Across different locations

• Scalability is always an issue
• May not want (or need) to manage DHCP servers at
every remote location

• You’re going to need a little help(er)
  
  • Send DHCP request across broadcast domains

Question 4

IP Address Management (IPAM)

Answer 4

• Manage IP addressing
  
  • Plan, track, configure DHCP
• Report on IP address usage
  
  • Time of day, user-to-IP mapping
• Control DHCP reservations
  
  • Identify problems and shortages
• Manage IPv4 and IPv6
  
  • One console