Which three statements describe a DHCP Discover message? (Choose three.)
a. The source MAC address is 48 ones (FF-FF-FF-FF-FF-FF).
b. The destination IP address is 255.255.255.255.
c. The message comes from a server offering an IP address.
d. The message comes from a client seeking an IP address.
e. All hosts receive the message, but only a DHCP server replies.
f. Only the DHCP server receives the message.
The Correct Answer and Explanation is:
Correct Answers:
b. The destination IP address is 255.255.255.255.
d. The message comes from a client seeking an IP address.
e. All hosts receive the message, but only a DHCP server replies.
Explanation:
The Dynamic Host Configuration Protocol (DHCP) is used in IP networks to automatically assign IP addresses and other configuration information to clients. The DHCP Discover message is the first step in the DHCP process, and it plays a critical role in the automatic IP configuration.
Let’s look at each correct statement:
✅ b. The destination IP address is 255.255.255.255
When a client sends a DHCP Discover message, it does not yet have an IP address. Therefore, it uses the broadcast IP address 255.255.255.255 to try to reach any DHCP server on the local network. This address ensures the message is received by all devices in the subnet.
✅ d. The message comes from a client seeking an IP address
The DHCP Discover message is initiated by a DHCP client. The client needs network configuration details, such as an IP address, subnet mask, and default gateway. It sends the Discover message to find available DHCP servers that can offer these details.
✅ e. All hosts receive the message, but only a DHCP server replies
Because the Discover message is a broadcast, all devices on the subnet receive it. However, only DHCP servers are programmed to respond with a DHCP Offer message. Regular hosts ignore the message.
Why the Other Options Are Incorrect:
❌ a. The source MAC address is 48 ones (FF-FF-FF-FF-FF-FF)
This is incorrect. The source MAC address in the Discover message is the actual MAC address of the client. The destination MAC address might be FF-FF-FF-FF-FF-FF (broadcast), but not the source.
❌ c. The message comes from a server offering an IP address
This describes a DHCP Offer message, not the Discover message. The Offer comes after the Discover.
❌ f. Only the DHCP server receives the message
This is false. Because it is a broadcast, all hosts receive the message, not just the DHCP server.
Summary:
A DHCP Discover message is a broadcast sent by a client to locate DHCP servers. It is received by all hosts, but only DHCP servers reply with an offer.