choosing resolution etc. per print job

[Michael Goffioul]

> > 1) edit /etc/cups/cupsd.conf, and set "ServerName" to "localhost"
> >    (ok if you don't plan to use the network browsing features of CUPS)
> 
> Thank you, this works.
> 
> But I still don't know exactly why it works. You say that, by default, CUPS
> forbids non-local connections. Why does changing the server name, CUPS
> reports, the connections from non-local to local? Is a connection to
> localhost considered non-local if the server doesn't identify itself as
> running on localhost but on something like mymachine.mydomain?

The problem is that CUPS identifies its printer queues using URI on
a given network. The URI has the form ipp://server:port/printers/name.
With this URI, a client can contact the needed server concerning its
printer queue over a network. By default, CUPS uses the computer
network name in the URIs, but in the same time it forbids any non
local connection (== connection from 127.0.0.1). This paradox leads
to failure in KDEPrint, which relies on the server name mentionned in
the printer URI. Indeed, KDEPrint tries to connect to the server
mentionned in the URI, and if it's not "localhost" it tries to open
a network connection (even if the server *is* "localhost" physically).
This connection gets refused by the server and KDEPrint cannot retrieve
the required information, like the printer driver. This problem has
been solved in KDE-3.2.x branch.
By setting "ServerName" to localhost, you force CUPS to use "localhost"
in its URI, such that KDEPrint tries now to open a local connection,
which succeeds.

> Has changing the server name from the default value to localhost further
> implications (probably concerning security)?

No, except that you should disable browsing as well, because it's
useless now.

Michael.

-- 
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Michael Goffioul		IMEC-DESICS-MIRA
e-mail: goffioul at imec.be	(Mixed-Signal and RF Applications)
Tel:    +32/16/28-8510		Kapeldreef, 75
Fax:    +32/16/28-1515		3001 HEVERLEE, BELGIUM
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