I switched from Xfinity to Astound recently and have some questions on security and how to ensure I am protected or if I even need to worry much at all. With Xfinity I had a simple setup, Modem connects to Xfinity via coax and then my network from there. With Astound I now have a ethernet connection in the apartment I can do what I want with. After some investigation connecting directly to it I can see around 100 different devices with their respective MAC addresses and names using advanced IP scanner. After seeing this I reconfigured everything to run through a router instead of a switch and now am only able to see their respective public IP addresses. The modem is managed by the ISP and not the landlord/building if it maters. I haven’t done any more configuration from there but should I be concerned about security with this setup? Its something I’m unfamiliar with and want to make sure I am not at much risk (at least compared to the original setup where I owned the modem).
In all likelihood, the ‘modem’ is a router and each apartment is on a switch port routed through the ISP’s router.
A firewall-only solution will protect the devices that you have connected to the ethernet port in your apartment. Juniper, Xophos, etc.
A firewall-only solution is not typical of consumer-grade equipment. If double-NATing is not a problem, your own router is the solution.