I have a customer who has installed a 6400 switch and has a number of printers attached to the network. Occassionally he is not able to print to the printers, but he is able to ping the devices and access the web pages of the printers. The printers network cards were initialy set to Auto, but we recently hard set speed of the printers network cards to 100 / full duplex. This change did not correct the problem. Are there settings onm the 6400 that we should change?