Let say I have an ASP.NEt application which is bound with more than 10 domains using host headers. Is one certificate is enough for me? or I need more than 1 certificate for each domain? If I need 1 certificate, then adding a new domain means reinstall the certificate?
There are multiple certificate types.
- You can have a wildcard cert
*.domain.comwhich is valid for all subdomains.
- You can have a single-name cert
host.domain.comwhich is only valid for this host
- You can have a multi-name cert
host2.domain2.com, this is called a SAN (Subject Alternative Name) Certficiate. They are often called "UC-Certificate" by cert vendors.
I'm not sure where the technical limit is on a SAN cert, but it's certainly more than 10 names.
If they are truely unique domain names, you can get a SAN (Subject Alternative Name) certificate. Most vendors will let you put about 40 domain names on one cert. If they are sub-domains, a wildcard cert is the way to go. For each of tjose options you only need 1 ip as the cert is valid for all listed domain names.