> fireholpath="/usr/sbin/firehol"
>
> sudo apt remove -y ufw
This is removing (maybe) your default firewall.
I presume "firehol" is a replacement, so I guess that's OK.
> sudo apt install -y firehol
firehol is a wrapper for iptables and according to the interwebs doesn't have have a GUI, but is configured using easy to understand plain text config files. Never seen it before myself until today's reference above.
ufw is the default Ubunutu firewall and is a front-end for configuring iptables. On it's launchpad site they say "...is [a] program for managing a netfilter firewall. It provides a command line interface and aims to be uncomplicated and easy to use". There are GUI apps available for ufw.
I think they compare with firewallD on the red-hat/fedora side of the things.
Given ufw/firehol manipulate iptables, Peter maybe be better off with ufw and one of it's GUI interfaces if he doesn't fully understand what he's doing. Close everything off and only open things you actually need with restrictions as appropriate.