IPv4 DHCP Fundamentals

Question 1

What does DHCP stand for?

Answer 1

Dynamic Host Control Protocol

Question 2

What does DHCP do and why is it beneficial?

Answer 2

• Dynamically assigns and configures settings for communicating on the network. IP address, default gateway, DNS servers and even boot servers
• Reduces the time spent configuring these setting manually

Question 3

Describe the DHCP process when a computer is added to the network.

Answer 3

• DORA
• Discover: the new computer needs an IP address and will send out a DHCP discover packet, looking for a DHCP server
• Offer: Upon receiving the discover packet the DHCP server will respond with an IP address offer, containing a unique IP and other configuration settings
• Request: The new computer receives the offer and responds with a request, asking to reserve that IP for itself
• Acknowledge: the DHCP server acknowledges the request and updates its lease database with the new IP address assignment. The new computer configures its network card with the assigned settings

Question 4

Briefly describe how DHCP server is configured on Window’s server.

Answer 4

• Open Server Manager and navigate to Tools>DHCP opening the DHCP server configuration
• Create a scope. Scopes identify the subnet which the server controls addresses for
• Configure the address pool. This is the range of IP addresses you want to server to dynamically assign
• Configure scope options. These include additional setting such as default gateway and DNS servers.

Question 5

What are address leases on a DHCP server? Where can these be found in Windows?

Answer 5

• Addresses leases are those IPs dynamically assigned by the DHCP server
• In Windows, the addresses assigned under a particular scope can be found on the Leases tab of that scope.

Question 6

What are address reservations on a DHCP server? How are they useful? Where can they be found and configured on a Windows server?

Answer 6

• Reservations are IPs set aside for specific machines.
• Useful in that you can make sure the same IP is assigned to critical devices such as other servers or printers
• In Windows, found under the scope dropdown for the scope in which you want to configure the reservation. The MAC address of the network card for which you want to create the reservation is needed.

Question 7

What is DHCP Relay and how is it useful?

Answer 7

• Configured on a router, relay forwards DCHP Discovers packets to a configured DHCP server on a remote network and facilitates the DORA process to get an IP address assigned
• Enables DHCP for whatever networks you like without having to have a dedicated DHCP server for that network