SSL Cert for private web server with azure authentication

Question

I have been trying to figure out if the below scenario is correct.

I have a website hosted internally by the company i work for. It only needs to be accessed by employees of my work. The server is on a private IP range. However my website authenticates using Azure and Microsoft Graph API. It is configured as a converged app as it uses the new Azure 2 libraries, one of the requirements is that the login page is https. I know i can do a self signed cert and i might do that as a stop gap, however i would prefer to do it properly.

There is no global DNS in place for the server, and it might not be possible to do so, so netbios name would be preferable, can i get an SSL cert for server1.companyname.domain.com ? I have looked on GoDaddy etc and i think that i can, but i dont want to spend the money to find my solution does not work.

Also, some users may need to access the site by IP depending on there location, is this even possible with https? i am guessing not.

I know this is some pretty basic stuff but i've never had to configure SSL before, not sure how i've gotten away with it for so long :)

Thanks

Answer 1

An internal certificate authority seems to be the way to go, whether this is OpenSSL or active directory. let's encrypt would be ideal but the DNS has to be public.