Sometimes you have to replace SSL certificates instead of updating them, e.g. if you switch from a web server SSL certificate to a wildcard certificate. The latter was my job today. In my case, the SSL certificate was used in a Microsoft Exchange 2016 deployment, and the NetScaler configuration was using multiple virtual servers. I’m using this little script for my NetScaler/ Exchange deployments.
When using multiple virtual servers, replacing a SSL certificate using the GUI can be challenging, because you have to navigate multiple sites, click here, click there etc. Using the CLI, the same task is much easier und faster. I like the Lean mindset, so I’m trying to avoid “waste”, in this case, “waste of time”.
Update or replace?
There is a difference between updating or replacing of certificates. When using the same CSR and key as for the expired certificate, you can update the certificate. If you use a new certificate/ key pair, you have to replace it. Replacing a certificate includes the unbinding of the old, and binding the new certificate.
Replacing a certificate
The new certificate usually comes as a PFX (PKCS#12) file. After importing it, you have to install (create) a new certificate/ key pair.
add ssl certKey wildcard_exp_20190712 -cert wildcard_exp_20190712.pem -key wildcard_exp_20190712.pem -passcrypt random -expiryMonitor ENABLED -notificationPeriod 90
Do yourself a favor and add the expiration date to the name of the certificate/ key pair.
Now you can unbind the old, and bind the new certificate. Please note, that this causes a short outage of your service!
unbind ssl vserver lb_vs_exchange_owa_https_443 -certkeyName exchange2016_exp_20180713 bind ssl vserver lb_vs_exchange_owa_https_443 -certkeyName wildcard_exp_20190712
SSL Cert Unbind Causing NetScaler Crash
You should check what NetScaler software release you are running. There is a bug, which is fixed in 12.0 build 57.X, which causes the NetScaler appliance to crash if a SSL certificate is unbound and a SSL transaction is running. Check CTX230965 for more details.