We recently installed some 4500 series routers and are utilizing public and private ip space with vlans. If an HP (only HP) printer is on the private IP space everybody except the users on the same private IP space can print to it. If we put it on public IP, it is usable by all. We have tried updating firmware on the printer to no avail. Besides replacing all HP printers to a different brand, does anyone have any ideas as to what may be the problem?