Stateful firewall

A stateful firewall is like a gatekeeper for your computer or network. It checks every piece of information that comes in or goes out, like checking who's knocking at your door before you let them in.

But a stateful firewall does more than that. It remembers the information it's already checked so it can save time later. For example, if a friend comes over to play and you let them in, you don't have to keep asking them who they are every time they leave and come back in. Your stateful firewall does the same thing with computer data.

It keeps track of the data that's been allowed in and out before so it can quickly decide whether new data is okay to let through or not. That way, it can catch any bad guys trying to sneak in and stop them before they can cause any harm.

So, think of a stateful firewall like your own personal doorman who doesn't let anyone in unless they're on the guest list. And he also has a great memory so he knows who's been in and out already.