Could I use Google DNS 18.104.22.168 and 22.214.171.124 instead of my ISP DNS?
The "work" domain is specific to my Active Directory network. I cannot give any advice on other platforms I do not use or have experience with. Sorry.
Anyone with Internet access gets at least 2 DNS server provided by your ISP. If you do not see them already configured on your PCs, call your ISP and ask about their IP numbers.
Security is always a bit tricky. It is always a balancing act of budget/time/risk. There are always better ways of reducing security risks but you have to stay within your budget and time/skill to implement and support the security mechanisms. We have a hardware firewall and our employees get educated on safe practices since the best security in the world can be rendered useless if misused and mismanaged. Stopping automated attacks is one thing, stopping your employees from doing stupid stuff is a whole 'nother game entirely. I also have an identical server gets automated OS updates and lets me know I need to update the production server.
As for the new thread, I will post an update with a link to it on this thread when it is done. I'm still working on it at the moment but I don't get a lot of time to work on this (currently building an automated interface between hospitals to share data more efficiently than paper). Getting to play with MySQL, PHP and vsftpd.