A technician has just installed a new firewall onto the network. Users are reporting that they
cannot reach any website. Upon further investigation, the technician determines that websites can
be reached by entering their IP addresses. Which of the following ports may have been closed to
cause this issue?

A.
HTTP

B.
DHCP

C.
DNS

D.
NetBIOS

Explanation:
DNS links IP addresses and human-friendly fully qualified domain names (FQDNs), which are
made up of the Top-level domain (TLD), the registered domain name, and the Subdomain or
hostname.
Therefore, if the DNS ports are blocked websites will not be reachable.