Are you managing multiple Sub-Domains on a single main domain? There are Wildcard SSL certificates that can help make your management needs much more simple. A Wildcard SSL certificate secures an unlimited number of Sub-Domains in addition to your main domain. Simply use an asterisk – for example *.mywebsite.com – during the CSR generation and you're covered. You can even re-issue the certificate if you add more Sub-Domains later on. It's a great tool and it really cuts down on the time it takes to manage your SSL Certificates.