War dialing is a very old attack and depicted in movies that were made years ago.

Why would a modem security tester consider using such an old technique?

A.
It is cool, and if it works in the movies it must work in real life.

B.
It allows circumvention of protection mechanisms by being on the internal network.

C.
It allows circumvention of the company PBX.

D.
A good security tester would not use such a derelict technique.

Explanation:
If you are lucky and find a modem that answers and is connected to the target network, it usually is less protected (as only employees are supposed to know of its existence) and once connected you don’t need to take evasive actions towards any firewalls or IDS.