Simplifying Network Printing with CUPS

One of CUPS' great advantages is that CUPS servers can communicate with one another and exchange lists of available printers. This process is known as browsing, and it can greatly simplify network printing configuration. Instead of manually defining print queues on each print client, you need only configure the clients to enable browsing and set up the print servers to share their printers. The second task is described in the preceding section, "CUPS Access Control"—you configure the /printers location so that all the clients can access the printers. Be sure to include both Allow and BrowseAllow directives in this definition. You must then enable browsing on both clients and servers. This task is accomplished by the following line prior to any location sections, on both the client and the server:

Browsing On

This directive is enabled by default with CUPS, but some distributions include a Browsing Off directive to disable it. On the server, you should also enable browsing for all the clients outside of the /printers location, using a line like this:

BrowseAddress 192.168.1.255

This line tells the system to accept browsing requests from the 192.168.1.0/24 network. As with other CUPS address specifications, you can provide this information in other forms, as well.

Once you have made these changes and have restarted the client and server print queues, you should see all the available network printers appear on the clients' printer lists, as revealed by the CUPS web-based configuration tools. It may take a few seconds, or potentially even minutes, for all these printers to appear, though, so be patient. CUPS is smart enough to keep printers from appearing multiple times. For instance, if you have two print servers, each server should detect the other's printer; however, the servers won't further propagate other servers' printer, so clients should show each printer just once. Printers shared through a non-IPP protocol, though, might conceivably appear multiple times if these printers are added to a print server whose printers are browseable via IPP.

Note Both the client and the server must use CUPS for browsing to work. You can configure a CUPS client to print to an LPD server much as you'd configure the system to print to a local printer, but you must specify the server's hostname and print queue name instead of a local device filename.

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