dddddddddddd | 4 years ago | on: Hacker deleted all of NewsBlur’s Mongo data and is now holding the data hostage
In production never ever use ufw or firewalld. Learn a few rules in iptables and that all or create a simple script.
The problem with ufw or firewalld(not only with this 2) they add so many rules in iptables, that a human can do very easy mistakes or the rules are not on your control.