T
Tony Whitmore
Hi all,
This was good one for me to have to think about on a Monday morning!
We have 5 HP LaserJet 5Ns, with JetDirect cards. These are the
workhorses of our IT rooms and are usually rock solid. (You can guess
where this is going, can't you?)
These printers have started misbehaving. All 5 of them. At the same
time. They should have 3 open ports on them:
23/telnet
515/lpd
9100/jetdirect
However, they've started closing some/all ports seemingly randomly.
One minute all three ports will be open, the next none. Sometimes one
or two of the ports are open. Thinking that the problems might be due
to the traffic on the network (I have read that the JetDirect cards
can sometimes get swamped by too much traffic) I have isolated one of
the printers on a hub with a single PC and no upstream link. However,
I still get these varying results from port scanning even in this
isolated environment. I had wondered if it was the act of port
scanning itself that was causing the ports to close, but I have used
nmap on them before without them turning up their toes.
No configuration changes have been made since Easter, and they've been
working solidly up until today. Given their age there is very little
information on HPs website. Googling hasn't turned up any helpful
results either. The most bizarre thing is that they've all started
having the problem at the same time. I've cleaned (it was worth a
shot!) the "test" printer, and performed a factory reset on it too.
Any advice appreciated.
Tony
This was good one for me to have to think about on a Monday morning!
We have 5 HP LaserJet 5Ns, with JetDirect cards. These are the
workhorses of our IT rooms and are usually rock solid. (You can guess
where this is going, can't you?)
These printers have started misbehaving. All 5 of them. At the same
time. They should have 3 open ports on them:
23/telnet
515/lpd
9100/jetdirect
However, they've started closing some/all ports seemingly randomly.
One minute all three ports will be open, the next none. Sometimes one
or two of the ports are open. Thinking that the problems might be due
to the traffic on the network (I have read that the JetDirect cards
can sometimes get swamped by too much traffic) I have isolated one of
the printers on a hub with a single PC and no upstream link. However,
I still get these varying results from port scanning even in this
isolated environment. I had wondered if it was the act of port
scanning itself that was causing the ports to close, but I have used
nmap on them before without them turning up their toes.
No configuration changes have been made since Easter, and they've been
working solidly up until today. Given their age there is very little
information on HPs website. Googling hasn't turned up any helpful
results either. The most bizarre thing is that they've all started
having the problem at the same time. I've cleaned (it was worth a
shot!) the "test" printer, and performed a factory reset on it too.
Any advice appreciated.
Tony