A user reports that some normally accessible external sites are not responding, but most other
sites are responding normally. Which of the following is MOST likely the cause?

A.
VLAN tag mismatch

B.
Wrong subnet mask

C.
Smurf attack

D.
Faulty routing rule

Explanation:
This happens when the DNS server is able to resolve the URL but there can be a conflicting route
pointing to somewhere else rather than to the correct device who is responsible for routing traffic
to the internet.