Yes, you can protect multiple sub-domains with a single SSL certificate.
Wildcard SSL certificates are used to achieve this goal. Additionally to "example.com" and "www.example.com" wildcard SSL protects all sub-domains, i.e. "*.example.com".
Price
Wildcard SSLs are more expensive than single-domain certificates. Our most popular Comodo Essential Wildcard certificate costs $115/year.
Advantages
Simplified certificate management is main reason to use Wildcard SSL. Imagine that you need to renew 100 certificates for your 100 sub-domains, that can be a nightmare. With a Wildcard SSL cert you will need to go through renewal process only once. That's much better, right? :)
- 22 Users Found This Useful