The helpdesk is receiving multiple calls about slow and intermittent Internet access from the finance
department. The following information is compiled:
Caller 1, IP 172.16.35.217, NETMASK 255.255.254.0
Caller 2, IP 172.16.35.53, NETMASK 255.255.254.0
Caller 3, IP 172.16.35.173, NETMASK 255.255.254.0
All callers are connected to the same switch and are routed by a router with five built-in interfaces. The
upstream router interface’s MAC is 00-01-42-32-ab-1a A packet capture shows the following:
09:05:15.934840 arp reply 172.16.34.1 is-at 00:01:42:32:ab:1a (00:01:42:32:ab:1a)
09:06:16.124850 arp reply 172.16.34.1 is-at 00:01:42:32:ab:1a (00:01:42:32:ab:1a)
09:07:25.439811 arp reply 172.16.34.1 is-at 00:01:42:32:ab:1a (00:01:42:32:ab:1a)
09:08:10.937590 IP 172.16.35.1 > 172.16.35.255: ICMP echo request, id 2305, seq 1, length 65534
09:08:10.937591 IP 172.16.35.1 > 172.16.35.255: ICMP echo request, id 2306, seq 2, length 65534
09:08:10.937592 IP 172.16.35.1 > 172.16.35.255: ICMP echo request, id 2307, seq 3, length 65534 Which of
the following is occurring on the network?

A.
A man-in-the-middle attack is underway on the network.

B.
An ARP flood attack is targeting at the router.

C.
The default gateway is being spoofed on the network.

D.
A denial of service attack is targeting at the router.