Been there done that. It’s much harder than it seems from this post. Your brain suffered severe damage, getting it to work again as good as possible takes huge amounts of energy and will power. Good job bro! (Watch yourself, don’t over do it)

Fail2ban does not listen on any port for it has no user interface. No interface at all actually. It’s just a process that monitors your logfiles and changes firewall rules and writes to syslog if you tell it to.

I run it on internet facing servers so I use a ‘regular’ install and never docker. I see no advantage for docker in this case, but one huge disadvantage: Docker changes a lot on the network side. It creates bridges, and picks IP’s all by itself. I hate that. (I know you can put in a lot of effort to manage it, but no thanks keep your ‘hands’ of my network config thank you)

I don’t use anything cloud based and much of my shit isn’t even allowed out to the internet.

It’s a drop in the ocean, for too many say “But it’s sooooo convenient and I’ve got nothing to hide” and open up all they got. Share camera’s with amazon, email address book with facebook etc. not realizing nor caring I make an appearance in their instances too and I DO mind.

It does not. It does not uses ports at all. Fail2ban monitors your logfiles and activates the firewall to block IP’s that matched your rules.

t.ex. You can block an IP that tried to access https://<url>/admin. You can block an IP that used wrong credentials x times to login on an ssh port. Or block one that tried to relay via your mailserver. The duration is configurable and alternative duration can be configured for recidivists.

And yes, you can whitelist IP’s to avoid locking yourself out. The possibilities are endless.

My usual additions:

1. Have the router to block portscanners
2. fail2ban on internet facing services.

That’s just the tip of the iceberg of printer issues. I’m in networking, don’t get me started on networking and security issues involved in printing “solutions”