This article applies as of PRTG 22

Modifying key length for Diffie-Hellman parameters

PRTG comes with a high security standard that makes your network monitoring as secure as possible. All communication in PRTG is secured by TLS where only the most secure ciphers are supported. We describe important security features of PRTG in the article What security features does PRTG include?

As of PRTG version 14.4.12, PRTG uses unique pre-defined Diffie-Hellman (DH) parameters with a 1024-bit key by default. This key length is sufficient for most scenarios, but if you want to enhance this key and generate a key that is longer than 1024 bits, you can do so as well. In this example, we'll show how you can manually generate a key with 2048 bits.

Creating a longer key for DH parameters

1. Open PowerShell as administrator on the PRTG core server system and navigate to the \cert subfolder of the PRTG program directory.
   Note: If PRTG is installed under the default path you can use the following command to navigate to the folder:
   cd "C:\Program Files (x86)\PRTG Network Monitor\cert\"
2. Enter the following commands:
   ..\openssl.exe dhparam -out dh.pem -2 2048Restart-Service PRTGCoreService -Confirm
3. Press Enter to generate a new key file and to restart the PRTG core server service.
4. Enter [Y]es when prompted to restart the PRTG core server service or restart the service manually at your convenience.
   Note: The new key length will only be applied after the PRTG core server service was restarted.

Done! PRTG now uses DH parameters with a 2048-bit key.