Steps to deploy a certificate fir User Portal

Question

We've recently purchased an official wildcard certificate for our domain at DigiCert. They actually do not provide a PKCS#12 File for download. 
 It's possible to create a copy of this certificate but I have to provide a certificate request .req file - then I receive a certificate as .cer file. This works well on MS Windows platforms in server applications like Exchange or IIS. 
 What I want to achieve is to have a valid+official certificate when users connect to the UserPortal. The WebAdmin should also use this certificate. 
 It seems the Sophos certificate system works completely different and I'm not sure where to start. I'm also not highly experienced in handling certificate deployment. 
 Can you give me a hint?

Louis-M · Accepted Answer

We use Digicert and we have thir certs on our UTM. Log into Digicert and you will find they have some free tools. Convert it to .pfx (as Bob says) and then import it. It's a straight forward process.

ChrisSoukup · Answer

I finally found an easy solution for creating a .pfx certificate that is accepted for upload on the Sophos UTM9. Since the wildcard certificate was initially created for our Exchange server it was possible to export it from there and giving it a password. 
 This article describes how to export the certificate from the server in PKCS #12 format (.pfx file) 
 https://technet.microsoft.com/en-us/library/cc771848(v=ws.10).aspx 
 After that I just added/uploaded it on the Sophos firewall at Webserver Protection -> Certificate Management and then selected it for WebAdmin on the HTTPS tab.