firewalld is the default firewall for RHEL, CentOS, Fedora, and openSUSE. Learning new things can be intimidating at first but after a quick tutorial I think you’ll find that
firewalld is easier to use for most firewall setups when compared to basic
DNF has replaced YUM as the package manager for Fedora 22 onwards and future RHEL/CentOS releases. Luckily, DNF and YUM are very similar, particularly for commonly used commands, but there are some differences. Below are some links I’ve found handy for getting familiar with DNF.