Intermittent Connectivity Issues
Question
A consultant is reviewing the following output after reports of intermittent connectivity issues: ? (192.168.1.1) at 0a:d1:fa:b1:01:67 on en0 ifscope [ethernet] ? (192.168.1.12) at 34:a4:be:09:44:f4 on en0 ifscope [ethernet] ? (192.168.1.17) at 92:60:29:12:ac:d2 on en0 ifscope [ethernet] ? (192.168.1.34) at 88:de:a9:12:ce:fb on en0 ifscope [ethernet] ? (192.168.1.136) at 0a:d1:fa:b1:01:67 on en0 ifscope [ethernet] ? (192.168.1.255) at ff:ff:ff:ff:ff:ff on en0 ifscope [ethernet] ? (224.0.0.251) at 01:02:5e:7f:ff:fa on en0 ifscope permanent [ethernet] ? (239.255.255.250) at ff:ff:ff:ff:ff:ff on en0 ifscope permanent [ethernet] Which of the following is MOST likely to be reported by the consultant?
Answers
Explanations
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A. B. C. D.B.
The output provided shows the ARP (Address Resolution Protocol) cache of a network device. ARP is used to map a network address (such as an IP address) to a physical address (such as a MAC address) used by network devices. The output shows the IP and MAC addresses of devices that have recently been accessed on the network.
The consultant is reviewing the output after reports of intermittent connectivity issues. Based on the output, the consultant is likely looking for clues as to what might be causing the connectivity issues. Let's examine the answer choices to determine which is the most likely:
A. A device on the network has an IP address in the wrong subnet. This answer choice suggests that a device on the network is misconfigured and has an IP address that is not valid for the subnet. However, the ARP cache output does not provide any information that would suggest this is the case. Therefore, this answer choice can be eliminated.
B. A multicast session was initiated using the wrong multicast group. This answer choice suggests that a multicast session has been initiated using the wrong multicast group, which could cause connectivity issues. However, there is no evidence in the ARP cache output to support this theory. Therefore, this answer choice can be eliminated.
C. An ARP flooding attack is using the broadcast address to perform DDoS. This answer choice suggests that an attacker is flooding the network with ARP requests using the broadcast address to perform a DDoS attack. The ARP cache output does show the broadcast address, which could be used in such an attack. However, the output also shows MAC addresses associated with legitimate network devices. Therefore, it is difficult to determine whether an attack is actually taking place. This answer choice is plausible, but not the most likely based on the evidence provided.
D. A device on the network has poisoned the ARP cache. This answer choice suggests that a device on the network has intentionally provided false information to the ARP cache, causing connectivity issues. This is the most likely scenario based on the evidence provided. The ARP cache output shows multiple MAC addresses associated with the same IP address, which is not normal behavior. This could be a sign that a device on the network is intentionally poisoning the ARP cache, causing intermittent connectivity issues.
Therefore, the most likely answer to this question is D. A device on the network has poisoned the ARP cache.
