Question 1

Routers send ICMP Redirect messages to hosts to indicate that a preferable route exists.

Accepted Answer

Routers use ICMP Redirect messages to inform a host that there's a more efficient route available for its traffic, typically suggesting that the host sends its packets directly to a better gateway on the same network.

Question 2

ICMP packets contain only three required fields after the IP header: Type, Code, and Checksum.

Accepted Answer

ICMP packets, after the IP header, indeed contain only three required fields: Type (which specifies the ICMP message type), Code (which provides further information about the type), and Checksum (used for error-checking the header data).

Question 3

Which of the following can hackers can use as part of a reconnaissance process to learn about active network addresses and active processes?
A)availability
B)ICMP
C)auto recovery
D)presence

Accepted Answer

ICMP (Internet Control Message Protocol) is used by hackers in the reconnaissance process to discover active network addresses and to map out network properties by sending echo requests and waiting for responses, thus identifying active devices on a network.

Question 4

What protocol protects the authentication and confidentiality of ICMPv6 exchanges?
A)IPsec
B)WPA2
C)PPTP
D)SHA-2

Accepted Answer

IPsec is designed to protect IP packets, including those used in ICMPv6 exchanges, ensuring authentication, confidentiality, and integrity of the data.

Question 5

Which of the following message types document when routing or delivery errors prevent IP datagrams from reaching their destinations?
A)ICMP Echo/Echo Reply
B)ICMP Source Quench
C)ICMP Time Exceeded
D)ICMP Destination Unreachable

Accepted Answer

ICMP Destination Unreachable messages are used to indicate that an IP datagram could not reach its destination due to routing or delivery errors.

Question 6

Which of the following utilities use route tracing to identify a path from the sender to the target host?
A)gateway
B)Traceroute
C)firewalking
D)auto-recovery

Accepted Answer

Traceroute is a network diagnostic tool used to track the pathway packets take from a source to a destination, identifying each hop along the way.

Question 7

Routers can use ICMP to provide a default gateway setting to a host (if the host requests assistance).

Accepted Answer

Routers use ICMP to provide a default gateway setting to a host if the host requests assistance.

Question 8

A host or router can send which of the following error message to indicate that the protocol defined in the IP header cannot be processed?
A)Code 2: Protocol Unreachable
B)Code 3:Port Unreachable
C)Code 4: Fragmentation Needed and Don't Fragment Was Set
D)Code 5: Source Route Failed

Accepted Answer

Code 2: Protocol Unreachable is the error message sent by a host or router to indicate that the protocol defined in the IP header cannot be processed. This is part of ICMP error messages used for network diagnostics.

Question 9

Which of the following types of messages serves to keep hosts apprised of networking conditions and problems, and equipped to use best paths around the network?
A)NTP messages
B)Path MTU messages
C)ICMP messages
D)GMT messages

Accepted Answer

ICMP (Internet Control Message Protocol) messages are used for error reporting and diagnostic functions in network communications, helping hosts to understand network conditions and problems, and to use the best paths around the network.

Question 10

Which message type supports functionality for reachability utilities like Ping and Tracert; essential when installing, configuring, and troubleshooting IP networks?
A)ICMP Echo/Echo Reply
B)ICMP Source Quench
C)ICMP Time Exceeded
D)ICMP Destination Unreachable

Accepted Answer

ICMP Echo/Echo Reply messages are used by utilities like Ping to check the reachability of a network device. These messages help in diagnosing and troubleshooting network connectivity issues.

Question 11

Which RFC defines a method for discovering a Path MTU (PMTU) using ICMP?
A)RFC 1191
B)RFC 1241
C)RFC 1542
D)RFC 1577

Accepted Answer

RFC 1191 defines the method for Path MTU Discovery (PMTUD) using ICMP messages, allowing devices to discover the maximum transmission unit size over the path of an internet connection.

Question 12

Which of the following message types permit a gateway (router) on a nonoptimal route between sender and receiver to redirect traffic to a more optimal path?
A)ICMP Echo/Echo Reply
B)ICMP Source Quench
C)ICMP Redirect
D)ICMP Destination Unreachable

Accepted Answer

ICMP Redirect messages are specifically designed to inform a host of a more optimal route for sending packets. When a router receives a packet but realizes there's a better path to the destination, it can use an ICMP Redirect message to advise the sending host of this more efficient route.

Question 13

With router advertising, the default Lifetime value for route entries is 10 minutes.
Indicate the answer choice that best completes the statement or answers the question.

Accepted Answer

The default Lifetime value for route entries in router advertisements is typically 30 minutes, not 10 minutes.

Question 14

Using which of the following as well as some manipulation of the TTL value in the IP header, Traceroute results provide a list of routers along a path, as well as the round-trip latency time to each router?
A)ICMP Echo Requests
B)ICMP paths
C)ICMP metrics
D)ICMP query messages

Accepted Answer

Traceroute uses ICMP Echo Requests along with manipulating the Time To Live (TTL) value in the IP header to identify the routers along a path and measure the round-trip time to each router.

Question 15

The value 0 in the IP header Protocol field denotes that an ICMP header follows the IP header.

Accepted Answer

The value 0 in the IP header Protocol field actually indicates the HOPOPT (IPv6 Hop-by-Hop Option), not ICMP. ICMP is represented by the value 1.

Question 16

Which of the following typically learn about routes through manual configuration of the default gateway parameter and redirection messages?
A)Packets
B)Firewalls
C)Ports
D)IP hosts

Accepted Answer

IP hosts typically learn about routes through the manual configuration of the default gateway parameter and redirection messages. This is essential for directing traffic from a local network to external networks.

Question 17

Which of the following processes is one method of obtaining a list of the active hosts on a network?
A)ICMP query
B)query
C)IP address scanning
D)firewalking

Accepted Answer

IP address scanning is a method of obtaining a list of the active hosts on a network by sending ICMP echo requests to a range of IP addresses.

Question 18

Which of the following enables a source to learn the currently supported MTU across an entire path, without requiring fragmentation?
A)Firewalking
B)Traceroute
C)Pathping
D)PMTU Discovery

Accepted Answer

Path MTU Discovery (PMTU Discovery) is a mechanism that allows a source node to dynamically discover and adjust to the smallest Maximum Transmission Unit (MTU) size on the path to a destination, thus avoiding fragmentation across the network path.

Question 19

Which of the following ICMP packet fields provide error detection for the ICMP header only?
A)Checksum
B)Type
C)Host
D)Code

Accepted Answer

The Checksum field in an ICMP packet is used for error detection, ensuring the integrity of the ICMP header and data. It helps in identifying any data corruption that might have occurred during the packet's transmission.

Question 20

Which of the following may a router or host use as a way to indicate that it is becoming congested or overloaded?
A)Checksum
B)Source Quench
C)GMT
D)PMTU

Accepted Answer

Source Quench messages are a mechanism used by routers or hosts to indicate that they are becoming congested. These messages request the sender to decrease the rate of messages sent, helping to alleviate the congestion.

Quiz 5: Internet Control Message Protocol

Routers send ICMP Redirect messages to hosts to indicate that a preferable route exists.

ICMP packets contain only three required fields after the IP header: Type, Code, and Checksum.

Which of the following can hackers can use as part of a reconnaissance process to learn about active network addresses and active processes?

What protocol protects the authentication and confidentiality of ICMPv6 exchanges?

Which of the following message types document when routing or delivery errors prevent IP datagrams from reaching their destinations?

Which of the following utilities use route tracing to identify a path from the sender to the target host?

Routers can use ICMP to provide a default gateway setting to a host (if the host requests assistance).

A host or router can send which of the following error message to indicate that the protocol defined in the IP header cannot be processed?

Which of the following types of messages serves to keep hosts apprised of networking conditions and problems, and equipped to use best paths around the network?

Which message type supports functionality for reachability utilities like Ping and Tracert; essential when installing, configuring, and troubleshooting IP networks?

Which RFC defines a method for discovering a Path MTU (PMTU) using ICMP?

Which of the following message types permit a gateway (router) on a nonoptimal route between sender and receiver to redirect traffic to a more optimal path?

With router advertising, the default Lifetime value for route entries is 10 minutes. Indicate the answer choice that best completes the statement or answers the question.

Using which of the following as well as some manipulation of the TTL value in the IP header, Traceroute results provide a list of routers along a path, as well as the round-trip latency time to each router?

The value 0 in the IP header Protocol field denotes that an ICMP header follows the IP header.

Which of the following typically learn about routes through manual configuration of the default gateway parameter and redirection messages?

Which of the following processes is one method of obtaining a list of the active hosts on a network?

Which of the following enables a source to learn the currently supported MTU across an entire path, without requiring fragmentation?

Which of the following ICMP packet fields provide error detection for the ICMP header only?

Which of the following may a router or host use as a way to indicate that it is becoming congested or overloaded?