Hi johnyb,
If this is still an issue please see this solution. If this does not help please consider contacting your support centre for further assistance.
We have installed the Xerox Scan Utility on several Desktops which are not on the same subnet with the Xerox phaser 8560 MFP but they are to communicate with it because they are able to send print job and open the web utility of the printer.
Also there is no firewall between the desktops and the MFP.
Any suggestions what would stop the MFP to communicate with the desktops ?