How to generate Self-signed Certificate with powershell for Veeam backup for Microsoft 365

Summary

For communication between our Veeam backup for Microsoft 365 portal and Microsoft 365 tenant you need to have a certificate. If you prefer you can use a self signed certificate. This article describes how you can do this.

Prerequisited

• Make sure you are admin on your windows system

• Make sure you run Powershell as an administrator

Getting Started

1. You can execute the following powershell scripts where you have to specify the following parameters before executing:
   Enter passwors string: ConvertTo-SecureString -String "Enter password" (note password will be displayed in clear text)
   Export-PfxCertificate: -FilePath C:\temp\$Certname.pfx -Password $pw (this will create the PFX file in C:\temp directory, make sure it exists.

2. script
   

   CODE

   # Create and export a self-signed certificate
   
   # Define certificate name
   $Certname = Read-Host “Enter Certificate Name”
   # Define expiration
   $YearsToExpire = Read-Host “How many years should this certificate be valid”
   Write-Host "Creating Certifcate $Certname" -ForegroundColor Green
   # Create certificate
   $Cert = New-SelfSignedCertificate -certstorelocation cert:\localmachine\my -dnsname $Certname -NotAfter (Get-Date).AddYears($YearsToExpire) -FriendlyName $Certname
   Write-Host "Exporting Certificate $Certname to $env:USERPROFILE\Desktop\$Certname.pfx" -ForegroundColor Green
   
   # Set password to export certificate
   $pw = ConvertTo-SecureString -String "Enter password" -Force -AsPlainText
   # Get thumbprint
   $thumbprint = $Cert.Thumbprint
   # Export certificate
   Export-PfxCertificate -cert cert:\localMachine\my\$thumbprint -FilePath C:\temp\$Certname.pfx -Password $pw
   

3. When executing the script it will ask you to provide the following information:
   Certificate name
   Years that the certificate should be valid

4. When creation of the PFX file is done
   

   

5. it has stored the certificate in your personal cert store
   

   

6. In this example it exported the pfx file to C:\temp