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
Honestly, OPNSense has some fairly decent reporting that can take you a fair ways. https://docs.opnsense.org/manual/reporting_traffic.html
Watching the traffic in those tools can highlight a lot of concerns. Is outbound wide open from all networks?
In general, I wouldn’t recommend doing auth at the network layer. You could do radius, AD, or something similar if that’s a concern. You could use Tailscale and create a mesh overlay - I’d do that before VPN. Going down this road can, of course, cause a lot of challenges with phones and other iot devices. I tend to keep the iot vlan barebones for that reason.