"Error: IP Address: Invalid arguments", when trying to add a static ARP entry.
If you have just tried to add a new static ARP entry and you are getting the error message "Error: IP Address: Invalid arguments" (see screenshot below), please do the following:
Step 1: Go to the hidden diag page.
To get to the hidden diag page, login to the unit, and replace "main.html" (in for instance https://192.168.168.168/main.html), with "diag.html" in your browser's address bar, so it becomes https://192.168.168.168/diag.html. This could also be http.
Step 2: Go toInternal Settings.
Step 3: Disable the option "Only allow ARP entries with unicast addresses".
Step 4: Click on "Accept".
Step 5: Click on "Close".
Step 6: Try adding the Static ARP entry again. It should work now.