Exporting and importing certificates
I often find myself needing to use the same SSL certificate on multiple servers. This might happen in the case where I have more than one IIS server serving up the same website and I am using some form of load balancing to split the traffic between them. This need may also arise when working with any form of hardware load balancer, as you sometimes need to import certificates onto not only the webservers themselves but into the load balancer box. Another example is when using wildcard certificates; when you purchase a wildcard, you typically intend to install it onto multiple servers.
Does this mean that I need to generate a new CSR from each server, and request a new copy of the same certificate multiple times? Definitely not, and in fact doing so could cause you other problems: remember that when a public CA re-keys a certificate—in other words, if you have already requested a certificate with a particular name and then come back again later...