Ever wondered what's a .pfx file? It's just a combination of both private key and the certificate and this file is usually used in Microsoft IIS Servers.

However, you can't use this file in Linux servers as both private key and the certificate are supposed to be individual files.

Here's how you can extract both private key and certificate files:

openssl pkcs12 -in file.pfx -nocerts -out privatekey.pem -nodes
openssl pkcs12 -in file.pfx -nokeys -out certificate.crt

Hope this tip helps you out!