I’m trying to switch our internal SharePoint over to https and I’m not sure if I’m doing everything correctly. Our farm consists of two WFE servers, the database server and an office web apps server. We have four web applications all with different urls currently:

 - http://mainsite   - http://mysites  - http://secondsite  - http://centraladmin  

I issued a CA certificate and applied it on port 443 on both WFEs for our main webapplication. I changed the default site to https://mainsite in AAM and added a mapping for the http://mysite to point back to it.

I then reset my search index and did a full crawl on the https site.

Everything looks good on the main site and I want to change the other sites over now. When I attempt to add a cert to the other sites I get a binding is already assign to port 443 notice. I believe this is because I need to specify a host header. Should I issue separate certs for the other three web application or issue one cert with all the address as a SAN entry?

Is there anything I’m not thinking of that could cause problems?