How to set up a redirect from sitename.ru to m.sitename.ru and back?

Question

Nginx

Good day to all.
How to properly set up a redirect from sitename.ru to m.sitename.ru (for a mobile client) and back from m.sitename.ru to sitename.ru if the page is not found in the mobile version? I know that you need to use cookies, but somehow I can’t register everything correctly
. Thank you in advance.

Answer 1

try to register correctly
How to make a redirect (redirect) to the mobile version of the site on the client side?
https://habrahabr.ru/post/108242/