If you are receiving the following “Error: Unknown Service Class” when creating or Editing a NAT policy there is a very simple explanation. This error will indicate that the Original Service and Translated Service are not using the same type of Protocol – (TCP/UDP). In the example below, the Original Service is just TCP 3391, but the Translated Service contains TCP and UDP 3389.
SonicWALL will come with built in services and it is important to know exactly what each of these services are referring to before using in any of your Rules or policies.
To solve this error, simply ensure that you select the correct service with the correct protocol. In the below example we can confirm that both are using TCP.