On my Linux server I have a keystore which contains SSL certificates and these certs are going to expire in 20 days. Before expiry of old certs, I have installed new SSL certificates to avoid any impact after expiry of old certs.
I have below questions.
Would new installed SSL certificates overwrite old SSL certificates which are going to expire? If NO, what is the reason?
It's regarding 1st one. If new SSL certificates don't overwrite old SSL certificates, then how to determine which certificates are working till expiry of old certificates?
If my old certs are from Godaddy and now, newly installed certs are from Thwate, will they overwrite? As their naming convention will be different and may be contents also, I guess.
Yes, they would overwrite the old SSL ceritificates. By overwriting the certificates (both key and actual certificate), you replace the certificates on your website. The visitors visiting your website will not see any error by this.
Right at the moment you replace the key and certificate and restart Apache (or the webserver software you use), it will be replaced for visitors.
I would recommend testing your website against SSLlabs, to check for any errors. Don't forget to check "do not show the results on the boards."