Can No Longer See Networked Printer

[Micros50]

On Mon, 2009-10-19 at 14:53 -0600, Karl Pearson wrote: 
> On Mon, October 19, 2009 1:06 pm, Micros50 wrote:
> > Hello,
> >
> > I have a small, in-house network consisting of several Linux machines
> > (running Fedora). One of the machines is attached to a printer and the
> > printer is published via Cups so it can be seen and utilized by all the
> > other machines on the network.
> >
> > Thus far everything works great. All machines can see the printer and
> > all machines can print to it.  That's just the way it should be...
> > EXCEPT!!!
> >
> > Except for one machine downstairs. It was seeing and printing to the
> > printer just fine. Now, all of a sudden, over the last couple of days it
> > no longer see's any networked printers. It was accessing and printing to
> > the networked printer just fine up until a couple days ago.  Now, it is
> > suddenly the only machine on my network that can't see or access the
> > printer.
> >
> > So, where do I begin to troubleshoot this problem ? The only possible
> > change that may have occur ed over the last couple of days is that Cups
> > may have been updated during a routine yum update. But all my other
> > machines have been updated similarly and they are not experiencing this
> > problem. Furthermore I checked the config files and everything looks
> > okay.
> >
> > Any ideas ? The machine that is having the issue is running Fedora 11.
> > But, so are most machines on my network, and they are having no issues
> > with printing.
> 
> Have you tried installing a new printer and letting it 'find' your
> networked printers? 

That was one of the first things I tried and it came up empty, iptables
was preventing it from seeing anything running on port 631.


> Also, have you tried using a network tool to see if
> that PC can see the network correctly, such as nmap or just telnet N
> where N = a port# you suspect, such as 631?
> 
> Just a thought. Give us the details of what you find, if anything.
> 
> Karl
> 

That would have been my next step. But it turned out to be an iptables
issue that probably occurred after an upgrade. As soon as I flushed the
firewall it was able to see the printers.  So all I had to do was change
my firewall/iptables rules. Now it's running fine with both seLinux and
iptables active.


John