How to change sharepoint company portal address?

Question

SharePoint

Hello, long before my employment, a corporate portal was raised on sharepoint. The portal can be accessed from a browser in three ways:
1. portal (default zone)
2. http://company_name/ (Intranet zone)
3. https://portal.company_name.ru/ (Internet zone, at this address portal accessible from outside).

How to make sure that the third option remains the main and only address? And when switching to the first days, a redirect to the third would work.

Do not offer a java script, it is obvious that something needs to be done here from the side of IIS and the Sharepoint Administration Center

Answer 1

Change the URL mapping as described in the comments above. Then you have to describe. Rewrite rules at the level of iis and web configs, for auto-redirects and redirects from one. URL to another, well, bindings at the iis level. I think this should be enough for you.
If you have previously used HostHeader on collections of sites, then you must either change them.

Answer 2

https://docs.microsoft.com/en-us/sharepoint/admin...

Answer 3

Definitely AAM. And in IIS, I would not touch anything