[PLUG] Turning off cups broadcast

Keith Lofstrom keithl at kl-ic.com
Tue Feb 20 08:31:09 PST 2007

Cups has a neat feature called autodiscovery, which allows computers
to share printers by default.  This feature is turned on by default,
no doubt so things "just work" for newbies.

In my case, I don't want to advertise my printer queues from my
machines, especially my laptop while roaming.  There are some lines
in /etc/cups/cupsd.conf:
# Browsing: whether or not to broadcast and/or listen for CUPS printer
# information on the network.  Enabled by default.

#Browsing On


One would think that adding the line:

Browsing Off

... would turn off the feature, but NO.   It keeps on spewing discovery
packets on port 631 to the broadcast address.  I finally turned this off
with the line:

BrowseInterval  0

Perhaps this will cause something odd to fail, like the guest printers
on my vmware host-only network.   But it is annoying sometimes;  I find
the damnedest printers popping up in /var/log/cups/error_log from while
roaming, no doubt from all the other laptops on the wireless broadcasting
their printers to the world.  At Linux clinic on Sunday, somebody was
broadcasting  store_4000  and  monkeyhouse,  for example.  Perhaps I
should have sent them a ransom note that would print when they got home.

On my home network,  I have iptables cranked up to high paranoia with
logging, and I was annoyed to see the broadcast packets from the laptop.
It took a while to figure out where they were coming from.   Hence this
message, for all the rest of you wondering where the ipp (port 631)
packets are coming from.


Keith Lofstrom          keithl at keithl.com         Voice (503)-520-1993
KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon"
Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs

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