Hey y'all,
I have a small network with opnsense firewall, a unify ap, some client in different subnets, vpn, DNS and some servers.
As I am completely self thought, I got everything to run reading the docs and forums, but I have no idea how to test if what I build is safe and stable.
Are there good up to date tools, or checklists one could follow to audit the different parts of the network (most important the opnsense config)?
What do you check if looking for security issues?
The network mostly relies on client separation through different subnets on different vlans, but I fear I dont understand how for example the vpn and the nas work together in detail to be sure there is no security implication I oversee.
Also: how do you handle client authentication for devices on the same subnet? I know IP/mac-adress ARP entries are easily spoofed and therefore not secure, but I haven't seen how to do it correctly
Radius is a part of 802.1x standard and for your threat model that does absolutely nothing. If a bad actor can access a device already in your network, then network level authentication doesn't do anything. For example it prevents from someone randomly plugging their device in your switch and getting access that way, or it only allows verified clients to your WLAN. But once the network connectivity is already established you need a totally different tools.
Mainly that means firewall on your network and/or servers. There's multiple ways to build that. You could get a separate firewall device to block access from the rest of the network to your devices or you can set up firewall for each of your things separately. All solutions have their own pros and cons and 'correct' solution depends on multiple variables.