I don’t know anything about firejail. I use this firewall, http://gufw.org
More info here, https://help.ubuntu.com/community/Gufw
I have it set to Allow outgoing and Deny incoming with the profile of Home (as opposed to Office or Public)
i sue that firewall too- i was hoping though to use firejail as it’;s a sandbox which further protects the computer- linux is pretty safe, but could always be made safer- just wish firejail was easier to install and to use and set up whitelists and blacklists like other sandbox programs do
I can’t really understand how to create a blacklist/whitelist in firejail- don’t even know where to put the commands- too complicated for my limited knowledge of linux