I have an Acer Aspire One netbook running Ubuntu 9.04 with a HP Laserjet 4200n connected directly to ethernet socket via network cable. The green network light on the network socket is on. There are no other devices wired to the network - just a straight cable connection between the netbook and the printer.

The problem is that I cannot ping the printer. I get "Destination Host Unreachable" message when I ping using:
(which is the correct printer IP address).

When I connect the cable to a different machine (a Windows XP box, direct connection) I can ping the printer fine from there. Hence the cable and the printer IP address must be correct. (Wireless networking works fine on the Aspire One, if that's relevant)

Any thoughts as to why this doesn't work from my Ubuntu machine? What am I missing here?