

We connect directly via IP at my friend’s house and only we are on the server, so no worries of griefers or internet randos.
Just in case you haven’t already, set up a whitelist. I’ve got a server running the same way, and I regularly get people trying to connect. I’ve also set up the firewall and blocked known scanners, but still get a few attempts.
You set the whitelist in Minecraft, and it uses your ID. I can’t remember exactly what Minecraft calls it, your player ID maybe. It doesn’t matter where you connect from then, as long as you’re logged in. I think it works the same way with pirated accounts too, but I haven’t got any here to check.
For the firewall, I’ve just been checking through the Minecraft log every now and then and banning the obvious bots and scanners, so that shouldn’t affect you either :)