DHCP fundamentals: Which statements correctly describe a DHCP Discover message at Layers 2 and 4?

Introduction / Context:
Dynamic Host Configuration Protocol (DHCP) automates IP address assignment. Understanding how the initial Discover message is transported helps diagnose why clients fail to obtain addresses across subnets or through security devices.

Given Data / Assumptions:

• Statement 1: Uses FF:FF:FF:FF:FF:FF as the Layer 2 destination (broadcast).
• Statement 2: Uses UDP as the Transport layer protocol.
• Statement 3: Uses TCP as the Transport layer protocol.
• Statement 4: Does not use a Layer 2 destination address.

Concept / Approach:
Before a host has an IP address, it cannot unicast an IP packet, so DHCP Discover is broadcast. At Layer 2, Ethernet broadcast MAC FF:FF:FF:FF:FF:FF is used. At Layer 4, DHCP rides over UDP: client source port 68 to server destination port 67.

Step-by-Step Solution:

Verification / Alternative check:
Packet traces (e.g., Wireshark) show BOOTP/DHCP over UDP with Ethernet broadcast for Discover. Relay agents (IP helpers) forward using unicast at Layer 3 while still UDP at Layer 4.

Why Other Options Are Wrong:

• “3 and 4” includes two false statements.
• “4 only” is incorrect because a destination MAC is required.
• Single-statement answers omit the correct pairing of 1 and 2.

Common Pitfalls:
Expecting DHCP to cross routers without a relay; filtering UDP/67-68; confusing ARP broadcasts with DHCP broadcasts.

Final Answer:
1 and 2