Fail2Ban VS masscan

now some things you need to think about: - cloud init - this will need to be secure so lock it down hard anything not needed an alternative OS to look at if you have the ability's is https://www.alpinelinux.org/ also as these devices are not that powerfull every extra agent / abstaction layer you add impacts performance need to look at low over head security https://www.crowdsec.net/ and https://github.com/fail2ban/fail2ban (if you call fail2ban security) - using certificates to authenticate ssh login

See https://github.com/fail2ban/fail2ban for beginner's guide, basically you set it up to monitor logfiles and it would act accordingly (plenty of built-in config to handle various daemons so you don't have to write yourself).

- Nginx & crowdsec/fail2ban if you are exposing your parts (services) to the public ( https://hub.docker.com/r/baudneo/nginx-proxy-manager, https://www.crowdsec.net, https://www.fail2ban.org )

— In /etc/fail2ban/action.d/cloudflare.conf I copied the file from https://github.com/fail2ban/fail2ban/blob/master/config/action.d/cloudflare.confand added my ‘cftoken’ and ‘cfuser’ on the bottom

https://github.com/fail2ban/fail2ban is a mature, easy to set up way to have some dynamic firewall rules that respond to attacks. There are more sophisticated options, but they are probably not worth the return on time investment for you.

You can create your own regexes for custom services: https://github.com/fail2ban/fail2ban/wiki/Developing-Regex-in-Fail2ban

Others seem to be (or were) experiencing this too: https://github.com/fail2ban/fail2ban/issues/3100

Can I get banned for mass scanning with https://github.com/robertdavidgraham/masscan or does it slow down any other vms from other persons?

Nope, this doesn't work any more. Shodan checks all ports (so any attackers using data from Shodan already know which ports you have open), and tools like masscan (https://github.com/robertdavidgraham/masscan) let you portscan the entire IPv4 address space in less than 10 minutes.

https://github.com/LogoiLab/mcsl https://github.com/robertdavidgraham/masscan

Changing the default port does nothing for security. It only prevents some basic brute force or default password scripts. Anyone is able to scan for it in no time anyway (https://github.com/robertdavidgraham/masscan).

But it should blow away the far-too-common belief that no-one's after you because you're not interesting enough. IPv4 is smaller than we think. It is not difficult to scan the entire ipv4 space in minutes. And every single one of those is going to knock your door on the way past.

I'm not sure about the article, but the blazingly-fast IP scanner sounds a lot like Masscan. It can scan the entire Internet in 5 minutes and has received a lot of press: https://github.com/robertdavidgraham/masscan . https://rushter.com/blog/how-masscan-works/ is one of many articles about it.

Here's an except from the masscan docs: