Most businesses install a firewall once, confirm it is running, and never
think about it again. That is a reasonable assumption for a lot of
technology, but it does not hold up for firewalls. A firewall that was
configured correctly three years ago is not necessarily configured
correctly today, and “it is turned on” is a very different thing from
“it is actually protecting you.”
Here is the gap that usually opens up. Firewall rules accumulate over
time: a temporary exception added for a vendor two years ago that was
never removed, a port opened for a project that finished months ago, an
outdated rule inherited from whoever set the network up originally. None
of these show up as a problem day to day. The firewall still says
“active.” But each one is a small hole in what is supposed to be your
main line of defense, and they tend to stack up quietly until someone
goes looking.
This gets missed for an understandable reason: nobody budgets time to
re-audit something that already works. IT teams and business owners
alike tend to treat a firewall as a one-time setup cost rather than an
ongoing practice, so once it is installed, it drops off the radar
entirely.
What proper firewall hygiene looks like is a periodic audit against a
known security standard, not just a glance to confirm the device is
still on. That means reviewing every rule and asking whether it is still
needed, checking that firmware and threat definitions are actually
up to date, and confirming the configuration matches current best
practice rather than whatever made sense when it was first set up. This
is typically benchmarked against frameworks like CIS (Center for Internet
Security), which give a concrete standard to audit against instead of a
vague sense that “it should be fine.”
A firewall that has never been re-audited since installation is not
necessarily doing anything wrong today. But nobody actually knows that
for certain, and for something that is supposed to be your first line of
defense, “probably fine” is a risky place to leave it.