Where is the hosts file on Mac, Windows, and Linux?

You need to open the hosts file. You already know why. You just cannot remember the path. Here it is for each OS, plus how to open it without fighting permissions. Paths OS Path macOS /etc/hosts Linux /etc/hosts Windows C:\Windows\System32\drivers\etc\hosts On Unix systems /etc/hosts is often a symlink into the real file. Edit the path above. Do not hunt for a second copy in your home folder. Open it on macOS Terminal: sudo nano /etc/hosts Enter fullscreen mode Exit fullscreen mode Or open it in your editor with elevated rights: sudo code /etc/hosts # or sudo vim /etc/hosts Enter fullscreen mode Exit fullscreen mode Save, then flush DNS: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder Enter fullscreen mode Exit fullscreen mode Finder will not let you edit /etc casually. Use the terminal or an editor launched with sudo. Open it on Windows Open Notepad as Administrator File → Open Go to C:\Windows\System32\drivers\etc\ Change the file type filter to All Files Open hosts Without admin rights Windows will open the file but refuse to save. Then flush DNS: ipconfig /flushdns Enter fullscreen mode Exit fullscreen mode Open it on Linux sudo nano /etc/hosts # or sudo vim /etc/hosts Enter fullscreen mode Exit fullscreen mode Flush depends on the stack. Common options: sudo resolvectl flush-caches # or sudo systemd-resolve --flush-caches Enter fullscreen mode Exit fullscreen mode What a normal line looks like 127.0.0.1 localhost 127.0.0.1 myapp.test # 203.0.113.10 staging.example.com Enter fullscreen mode Exit fullscreen mode Rules that save time: IP first, hostname second Spaces or tabs both work # comments out the rest of the line One hostname per line is easier to read than a long list Quick check after editing # macOS / Linux ping -c 1 myapp.test # or getent hosts myapp.test Enter fullscreen mode Exit fullscreen mode Windows: ping myapp.test Enter fullscreen mode Exit fullscreen mode If the IP in the reply is wrong, the hosts line did not apply yet. Flush DNS and try again before changing the app. Common mistakes Editing a copy in Downloads instead of the system file Saving without admin rights (Windows especially) Leaving a # in front of the line you meant to enable Forgetting the DNS flush Using a real public TLD like .com for local names when .test would avoid surprises Bookmark the path for your OS. You will need it again. If you switch hosts a lot, a small desktop manager helps keep profiles and DNS flush in one place: Locahl.