I’ve spent some time searching this question, but I have yet to find a satisfying answer. The majority of answers that I have seen state something along the lines of the following:

  1. “It’s just good security practice.”
  2. “You need it if you are running a server.”
  3. “You need it if you don’t trust the other devices on the network.”
  4. “You need it if you are not behind a NAT.”
  5. “You need it if you don’t trust the software running on your computer.”

The only answer that makes any sense to me is #5. #1 leaves a lot to be desired, as it advocates for doing something without thinking about why you’re doing it – it is essentially a non-answer. #2 is strange – why does it matter? If one is hosting a webserver on port 80, for example, they are going to poke a hole in their router’s NAT at port 80 to open that server’s port to the public. What difference does it make to then have another firewall that needs to be port forwarded? #3 is a strange one – what sort of malicious behaviour could even be done to a device with no firewall? If you have no applications listening on any port, then there’s nothing to access. #4 feels like an extension of #3 – only, in this case, it is most likely a larger group that the device is exposed to. #5 is the only one that makes some sense; if you install a program that you do not trust (you don’t know how it works), you don’t want it to be able to readily communicate with the outside world unless you explicitly grant it permission to do so. Such an unknown program could be the door to get into your device, or a spy on your device’s actions.

If anything, a firewall only seems to provide extra precautions against mistakes made by the user, rather than actively preventing bad actors from getting in. People seem to treat it as if it’s acting like the front door to a house, but this analogy doesn’t make much sense to me – without a house (a service listening on a port), what good is a door?

  • Kalcifer@sh.itjust.worksOP
    1·
    5 months ago

    I think I was going for the firewall as a means if perimeter security.

    Are you referring to the firewall on the router?

    it’s fairly uncommon that people go wardriving

    Interesting. I hadn’t heard of this.

    That may be isolating the cheap chinese consumer electronic with god knows which bugs and spying tech from the rest of the network.

    As in blocking or restricting their communication with the rest of the lan in the router’s firewall, for example? Or, perhaps, putting them behind their own dedicated firewall (this is probably superfluous to the firewall in the router though).

    But you might also be able to use a conventional firewall (or a VPN) to restrict access to that software to trusted users only

    For clarity’s sake, would you be able to provide an example of how this could be implemented? It’s not immediately clear to me exactly what you are referring to when combining “user” with network related topics.