I have two domain names, let's call them example.com and example.org. Originally, example.com redirected with a 301 redirect to example.org. Now I would like to reverse it, so example.org redirects to example.com. I understand that 301 redirects are cached in Firefox. I am able to clear the cache in Firefox and get the new website. My question is, for other users, how long is the 301 redirect at example.com cached before Firefox goes and checks again to see if anything has changed? Another related question: Let's say I add a 301 redirect on example.org to example.com. Then a user who has the old 301 redirect on example.com in their cache tries to visit example.com. Firefox will send them directly to example.org, and they will then get a 301 redirect back to example.com. What will Firefox do then?