Selfhosted

A port is not secure or insecure. The thing that can lead to security risks is the service that answers that port.

Use strong authentication and encryption on those services and keep them up to date.

I would use something like wireguard, or another VPN service you can host yourself if your router supports it natively.

From the looks of it Minecraft servers seem to have dogshit authentication, so using some form of private network setup is going to be your best move.

as long you are only forwarding Minecraft's 25565 port from your router to your server machine, it should be fine. Just make sure to keep Online mode on, use the whitelist, and get your plugins from trusted sources. Otherwise I wouldn't worry too much.

I see others recommending VPN solutions like zerotier for your friends to connect to; I don't personally feel like this is necessary, and (in my experience), making your friends do more technical setup than just connecting to the server is often a big turn-off.

Bonus: If you ever take a peek at your server logs while it's running (and exposed to the Internet, if you avoid said VPN solutions), you might notice a lot of weird connections from IPs and usernames you don't recognize. These are server scanners and threat scanners that look for vulnerable servers to connect to and exploit. This is normal and you'll be fine as long as you keep that whitelist and stay up-to-date on developments in the server admin space.

Why is port 22 open? Is this on your router as well or just the server?

This is SSH, which you should pretty much never have open (to the internet! Local is fine) MC is by default 25565. You will have every bot on the internet probing that port.

More effort than I would consider. I'd just allow all traffic incoming on that port. I'd only consider whitelist if someone was giving me grief. Even then that would be after blacklisting an IP wasn't solving my problem.

if I were you, I would do IP whitelisting at the firewall instead of or besides the Minecraft server

In the old days, it used to be a problem because everyone just connect their windows 98 desktop with all their services directly exposed to the internet because they’re using dial up internet without the concept of a gateway that prevents internet from accessing internal resources. Now days, you’re most likely behind your ISP router that doesn’t forward ports by default, and you’re only exposing the things you’d actually want to expose.

For things you’d actually want to expose, having a service on the default port is fine, and reduces the chances of other systems interacting with it failing because they’d expect it on the default port. Moving them to a different port is just security through obscurity, and honestly doesn’t add too much value. You can port scan the entire public IPv4 space fairly quickly fairly cheaply. In fact, it is most likely that it’s already been mapped:

https://www.shodan.io/host/

Keeping the service up-to-date regularly and applying best practices around it would be much more important and beneficial. For SSH, make sure you’re using key based authentication, and have password based authentication disabled; add fail2ban to automatically ban those trying to brute force. For Minecraft, online mode and white listed only unless you’re running a public one for everyone.

IP white lists and firewall exceptions will help, but exposing ports on your home router is almost always a bad idea, especially for something as trivial as a game server.

I would highly recommend Tailscale. It's free for up to 3 users, and if you have more friends than that, I would have them all sign up with free accounts and then share your laptop device with their tailnets.

It's very easy to setup and use, costs nothing, and will be far more secure than opening ports and trying to set up IP white lists, protocol limitations, etc.

Tailscale creates something called an "overlay network" it's basically a virtual LAN that exists on top of your real network and can be extended to other people and devices over the internet. It's fully encrypted, fast, and like I said, very easy to set up.

are you sharing a server solely to play with friends?

You could consider using something like zerotier to create a private network

assuming they are not behind a CGN whitelisting your mates place should be OK. But I would also move SSH away from a well known port. In the event something happens to the whitelist, crawlers will not jump on you straight away.

You cant. You can only do your best to make it as secure as possible, but given enough time, someone can break it.

Basic tips:

• don't run any services on their defaults ports
• don't allow password auth for any exposed service. Ever.
• run intrusion detection (fail2ban for simple ssh / Crowdsec for something a little beefier)

For ssh specifically, lock down your sshd config, make sure only key-based auth is enabled, and maybe as an extra step, create a dedicated user, and jail it by only allowing it access for the commands you need to interact with.

More or less. The biggest issue is if your or their IP address changes, it'll stop working.

I don't know what Minecraft's track record is on security, but I assume it's not great. Ideally, you'd also put public facing services in a DMZ, so that if they do get compromised, they can't reach anything else.

It is all about risk management. What you are doing now is pretty solid. It might be easier to have them use a mesh VPN like netbird or tailscale