A technician is tasked with troubleshooting a network’s slowness. While troubleshooting, the technician is
unable to ping any external websites. Users report they are able to access the sites using the web browsers.
Which of the following is the MOST likely cause?

A.
ICMP traffic being blocked by the firewall

B.
VLAN hopping

C.
TACACS misconfiguration

D.
MTU black hole

Explanation:
https://www.bleepingcomputer.com/forums/t/459888/why-i-cant-i-ping-any-website-although-i-can-access-them/