A lightning conductor alone does not provide protection.
Rod is only as effective as its earth ground. Same earthing
system that would also protect those interior network cables
from utility transients.

You cannot install the best and least expensive earthing
(Ufer ground) because the foundation already exists. Next
best alternative is a halo ground. This utility demonstrates
concepts that cost least during new construction:
http://www.cinergy.com/surge/ttip08.htm

Neither lightning rod nor surge protectors define
effectiveness of transient protection. Quality of that system
is defined by the single point earth ground.

John Borman wrote:
Lightning conductor(s)?

Never thought of that