1.
Which one of the following options must a host on an Ethernet network know about a destination in order to send an Ethernet frame to that destination?
Correct Answer
C. MAC address
Explanation
In order to send an Ethernet frame to a destination on an Ethernet network, a host must know the MAC address of that destination. The MAC address is a unique identifier assigned to each network interface card (NIC) on the network. It is used to identify the specific device to which the frame needs to be sent. The receiving port number, IP address, and window size are not relevant to sending an Ethernet frame on an Ethernet network.
2.
On which OSI layer or layers does ARP operate?
Correct Answer
A. Between Layer 2 and Layer 3
Explanation
ARP (Address Resolution Protocol) operates between Layer 2 and Layer 3 of the OSI model. This protocol is responsible for mapping an IP address to a physical (MAC) address on a local network. It is used to resolve IP addresses to MAC addresses in order to facilitate communication between devices on the same network. ARP operates at Layer 2 to obtain the MAC address of a device in the same network, and at Layer 3 to determine the IP address of the destination device.
3.
ARP messages are sent using which Ethertype designation in the frame header?
Correct Answer
D. 0x0806
Explanation
ARP messages are sent using the Ethertype designation 0x0806 in the frame header. Ethertype is a field in the Ethernet frame header that identifies the protocol encapsulated within the frame. In this case, 0x0806 indicates that the frame contains an Address Resolution Protocol (ARP) message. ARP is used to map an IP address to a MAC address on a local network.
4.
Which one of the following options is the type of request that is sent by a host to discover the MAC address belonging to an IP address?
Correct Answer
B. ARP request
Explanation
An ARP (Address Resolution Protocol) request is sent by a host to discover the MAC address belonging to an IP address. ARP is used to map an IP address to a corresponding MAC address on a local network. When a host wants to communicate with another host, it needs to know the MAC address of the destination host. So, it sends an ARP request to the network asking for the MAC address associated with the given IP address.
5.
Which one of the following options is the MAC address that a host would use to send broadcast messages if its own MAC address is 0800:0222:2222?
Correct Answer
D. FFFF:FFFF:FFFF
Explanation
The MAC address FFFF:FFFF:FFFF is the correct answer because it represents the broadcast address. In Ethernet, the MAC address FFFF:FFFF:FFFF is used to send a frame to all devices on the network. When a host wants to send a broadcast message, it sets the destination MAC address to FFFF:FFFF:FFFF so that it is received by all devices on the network.
6.
Which two of the following options are common DHCP attacks? (Choose two.)
Correct Answer(s)
A. DHCP starvation
C. Rogue DHCP server
Explanation
DHCP starvation is a common DHCP attack where an attacker exhausts all available IP addresses in a DHCP server's address pool, preventing legitimate devices from obtaining an IP address. Rogue DHCP server is another common attack where an attacker sets up a fake DHCP server on a network, tricking devices into connecting to it and providing sensitive information. Both of these attacks exploit vulnerabilities in the DHCP protocol to disrupt network connectivity and potentially gain unauthorized access to network resources.
7.
How many messages are exchanged in a DHCP transaction?
Correct Answer
D. Four
Explanation
In a DHCP transaction, four messages are exchanged. The first message is the DHCPDISCOVER, which is sent by the client to discover available DHCP servers. The second message is the DHCPOFFER, which is sent by the server in response to the DHCPDISCOVER, offering the client an IP address. The third message is the DHCPREQUEST, which is sent by the client to request the offered IP address from a specific server. Finally, the fourth message is the DHCPACK, which is sent by the server to acknowledge the client's request and provide the client with the offered IP address.
8.
What is the destination port defined in the DHCP Discover message?
Correct Answer
D. 67 UDP
Explanation
The destination port defined in the DHCP Discover message is 67 UDP. This is because DHCP (Dynamic Host Configuration Protocol) uses UDP (User Datagram Protocol) as the transport protocol. The destination port 67 is used by the DHCP server to receive and process the DHCP Discover messages sent by the client.
9.
What is the destination port defined in the DHCP Offer message?
Correct Answer
C. 68 UDP
Explanation
The destination port defined in the DHCP Offer message is 68 UDP. DHCP (Dynamic Host Configuration Protocol) uses UDP (User Datagram Protocol) as the transport protocol. Port 68 is the well-known port number assigned to DHCP client/server communication. The DHCP Offer message is sent by the DHCP server to offer configuration parameters (IP address, subnet mask, gateway, etc.) to a DHCP client. Therefore, the correct answer is 68 UDP.