I currently have a home server which I use a lot and has a few important things in it, so I kindly ask help making this setup safer.
I have an openWRT router on my home network with firewall active. The only open ports are 443 (for all my services) and 853 (for DoT).
I am behind NAT, but I have ipv6, so I use a domain to point to my ipv6, which is how I access my serves when I am not on lan and share stuff with friends.
On port 443 I have nginx acting as a reverse proxy to all my services, and on port 853 I have adguardhome. I use a letsencrypt certificate with this proxy.
Both nginx, adguardhome and almost all of my services are running in containers. I use rootless podman for containers. My network driver is pasta, and no container has "--net host", although the containers can access host services because they have the option "--map-guest-addr" set, so I don't know if this is any safer then "--net host".
I have two means of accessing the server via ssh, either password+2fa or ssh key, but ssh port is lan only so I believe this is fine.
My main concern is, I have a lot of personal data on this server, some things that I access only locally, such as family photos and docs (these are literally not acessible over wan and I wouldnt want them to be), and some less critical things which are indeed acessible externally, such as my calendars and tasks (using caldav and baikal), for exemple.
I run daily encrypted backups into OneDrive using restic+backrest, so if the server where to die I believe this would be fine. But I wouldnt want anyone to actually get access to that data. Although I believe more likely than not an invader would be more interested in running cryptominers or something like that.
I am not concerned about dos attacks, because I don't think I am a worthy target and even if it were to happen I can wait a few hours to turn the server back on.
I have heard a lot about wireguard - but I don't really understand how it adds security. I would basically change the ports I open. Or am I missing something?
So I was hoping we could talk about ways to improve my servers security.
Minimum open services is indeed best practice but be careful about making statements that the attack surface is relegated to open inbound ports.
Even Enterprise gear gets hit every now and then with a vulnerability that's able to bypass closed port blocking from the outside. Cisco had some nasty ones where you could DDOS a firewall to the point the rules engine would let things through. It's rare but things like that do happen.
You can also have vulnerabilities with clients/services inside your network. Somebody gets someone in your family to click on something or someone slips a mickey inside one of your container updates, all of a sudden you have a rat on the inside. Hell even baby monitors are a liability these days.
I wish all the home hardware was better at zero trust. Keeping crap in isolation networks and setting up firewalls between your garden and your clients can either be prudent or overkill depending on your situation. Personally I think it's best for stuff that touches the web to only be allowed a minimum amount of network access to internal devices. Keep that Plex server isolated from your document store if you can.