A PKCS12-formatted certificate file can be created using Linux system with OpenSSL. To create a PKCS-12 formatted certificate file, one needs to have two main components of the certificate:
For example, the Apache HTTP server on Linux has its private key and certificate in these locations:
/etc/httpd/conf/ssl.key/server.key
/etc/httpd/conf/ssl.crt/server.crt
With these two files available, run the following command:
openssl pkcs12 -export -out out.p12 -inkey server.key -in server.crt
In this example out.p12 become the PKCS-12 formatted certificate file and server.key and server.crt are the PEM-formatted private key and the certificate file respectively.
After running the openssl command, you are prompted for the password to protect/encrypted the file. After choosing the password, the creation of the PKCS-12-formatted certificate file is complete, and it can be imported into the appliance.