I have a website what is now at development state and can be accessed by IP in two ways: at internal company network site can be accessed by 198.162.0.10/WebSite and from Internet 212.19.10.50:1234/WebSite

When user goes to 212.19.10.50:1234 it's redirected by routing to 198.162.0.10 with 443 port for https.

How can I install server certificate in my case? I need to make it work without certificate issues both at internal and external network.

Is it possible to create 2 certificates for one site to make IIS select prober certificate in my case?

And what SAN inside certificates subject have to be for external network? External IP?