How safe is my computer when I’m working offline? Does a router box increase safety?
If you are not connected at all to Internet, you are certainly safe against dangers coming from the net, but you are not 100% safe because something wrong can still enter in your machine with an USB pendrive or a floppy or another computer from a local network for example.
So if you are not connected at all to the net, a router will make no difference, but an antivirus software and a software firewall installed in your computer are certainly useful.
If you are still connected to Internet even if you are working offline, then the router is certainly a good protection (and again both a firewall and an antivirus software should be installed in your machine).
If you use Linux, moreover, you have another level of protection, because of the intrinsic security of this operative system and the (relative) lack of virus and other malwares affecting these systems
geno888. Thanks for the the information.