Hello. I need to use hosts file in my Whonix-Workstation instance in order to associate one domain name to a specific IP address for my personal research needs. Is it possible? How to specify an IP address to a domain name in Workstation?
It’s possible but discouraged as it has grave disadvantages.
By default, Tor Browser is using a Tor SocksPort (stream isolation), therefore ignores /etc/hosts file.
In Whonix, you’d have to disable transparent proxying in Tor Browser and make it use system default networking. It would still be using Tor (transparent proxying thanks to Whonix-Gateway) but that would break stream isolation. Therefore discouraged.
See these chapters for introduction:
Instructions how to make Tor Browser use system default networking (breaks stream isolation):