Single SSL certificate, multiple sites?

Question

I asked this as part of another question, but I feel that it should have its own:

Using a shared hosting plan, is there a way to protect multiple domains (assuming the host allows multiple domains under the same plan) with a single SSL certificate? I know that private SSL certificates require a dedicated IP address, but I'm looking for a job (I would rather not sign up for additional / better cost-saving plans, and I really don't want to outsource authentication ... to OpenID). Any ideas?

(I don't think wildcard certificates are an option since they are very expensive ...)

Answer 1

In principle, no, not in terms of shared hosting.

When you have several websites sharing an IP address, the server knows which site should route using the Host header. SSL encrypts the entire request and response, including the host header, and the web server does not know which SSL certificate to use to crack the message before trying to route it, so the SSL site must have a dedicated IP address.

Answer 2

As I mentioned in your other question, just ask your host for a dedicated IP address for each domain that requires SSL. This is a fairly simple request. If they cannot do this, it may be time to go shopping for another host, as it seems that you have outgrown what your host can provide you.

Answer 3

As for costs: the cost of certificates depends on whether you use self-signed certificates or certificates from a free certification authority or certificates from an expensive certification authority. Of course, for self-signed or free certificate authorities, your users must confirm that they trust CA in a web browser. Check out CACert for inexpensive certifications.

As for your initial question: the recommended RFC 3280 approach is to populate all host names in the subjectAltName extension, see section 4.2.1.7 of the RFC. Regardless of whether the CA wants to provide you with a certificate with a completed extension, it again depends on the certification authority.