So... Hopefully; this is the right place for this question. I need more Ethernet ports on my home network. Sadly, we already have an old router connected to the main router and we still need more ports.

I feel dumb for asking; but, I just would like to double check.

Would the devices connected to the switch be "protected" by the Main router's firewall? ? Up to this point I have assumed that was the case; but, a co-worker is convinced that is not the case [ I believe he is thinking of a situation in which the switch (un-managed) is before an access point].

[It would go modem to main router; main router then has the switch and old router connected to it.