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.
Something you might want to look into is using mTLS, or client certificate authentication, on any external facing services that aren't intended for anybody but yourself or close friends/family. Basically, it means nobody can even connect to your server without having a certificate that was pre-generated by you. On the server end, you just create the certificate, and on the client end, you install it to the device and select it when asked.
The viability of this depends on what applications you use, as support for it must be implemented by its developers. For anything only accessed via web browser, it's perfect. All web browsers (except Firefox on mobile...) can handle mTLS certs. Lots of Android apps also support it. I use it for Nextcloud on Android (so Files, Tasks, Notes, Photos, RSS, and DAVx5 apps all work) and support works across the board there. It also works for Home Assistant and Gotify apps. It looks like Immich does indeed support it too. In my configuration, I only require it on external connections by having 443 on the router be forwarded to 444 on the server, so I can apply different settings easily without having to do any filtering.
As far as security and privacy goes, mTLS is virtually impenetrable so long as you protect the certificate and configure the proxy correctly, and similar in concept to using Wireguard. Nearly everything I publicly expose is protected via mTLS, with very rare exceptions like Navidrome due to lack of support in subsonic clients, and a couple other things that I actually want to be universally reachable.
mTLS is great and it's a shame Firefox mobile still doesn't support it.