Can a single firewall cover multiple modules?
One of my players and I have been discussing the issue. Every time the book talks about firewalls it mentions them covering "modules" plural, but my player thinks this is an indefinite plural, and that if a single firewall could cover multiple modules, there would be no reason to include the following passage from page 217:
"A computer can have multiple firewalls to block off multiple modules, but no one module can be protected by more than a single firewall"
He thinks the first part of that sentence means that you need multiple firewalls to block off multiple modules, while I think it reads as saying that you "are allowed" to have multiple firewalls, each protecting different sections of the system.
Can anyone clarify this?