混合环境下的打印方法的选择。

So we share our printer via IPP using CUPS. What the heck is IPP? It's just printing overHTTP. Why use IPP versus, say, Windows Printer Sharing? Simple: we've got a mixedenvironment of Windows XP, Windows 7, OS X 10.6, OS X 10.7, Fedora, Ubuntu, and CentOSworkstations. IPP is supported by all of them. Plus, I could get AirPrint to work on it,which means you can add iOS in that list of Operating Systems above.

So obviously you need to get CUPS to work first.

yuminstallcupsghostscriptusbutils

So there's the cups package, ghostscript, and usbutils. Since most printers these days areconnected via USB, it's always nice to have usbutils installed. Ghostscript is neededsince most printers don't really support PostScript so I install it just in case.

So once you've got those installed, you need printer drivers. With so many differentprinter manufacturers, I leave that up to you, dear reader, as to how to install it.You'll usually need a PPD file. NOTE: if you're printer is supported via foomatic orgutenprint, you can install drivers via:

yuminstallfoomaticgutenprint-foomatic

This should install most drivers available. For example, we have an old Samsung ML-1510that is supported by foomatic. We do have a newer Samsung ML-1860 that isn't. Thatrequired me to download and install Samsung's Unified Printer Driver (ugh). Its installscript installed a bunch of .desktop files for every account on our server. So I had tosearch the entire server and remove all of these useless files. To Samsung: sheesh. Thisalso installed an initscript called smfpd, which is a daemon for parallel port printers.Again, sheesh. You can't disable this from startup via chkconfig. There is a commented out"exit 0" near the start. Uncomment that and the daemon should stop running on startup.Make sure you stop the daemon first as it consumes a bit of CPU and memory. Sheesh. Sorryfor the semi-rant.

Anyway, the default CUPS configuration only allows access to localhost. Since I don'tworry too much about security, and you can secure it after, I change the following in/etc/cupsd.conf:

I add the following:

ServerAlias*Port631

which makes the server listen to any hostname (our server has a CNAME to it calling it'printer01') on port 631.

Then I make sure to change all "Order deny,allow" to "Order allow,deny" and add an "Allowall" to everything after. This way, I can now remotely access the web GUI at:

http://hostname:631/

Change hostname for whatever you call your print server. If at anytime you're asked for ausername and password, use your server's root account. So now that you have access to theweb GUI, simply add your printer here.

Now you should be able to start CUPS:

servicecupsstart&&chkconfigcupsonTest your printer

So you should be able to add your printer to your workstations. The whole URL to yourprinter is:

http://hostname:631/printers/PRINTERNAME

or:

ipp://hostname/printers/PRINTERNAME

Special note for Mac users: for the "Queue" setting, make sure you include the"printers" portion. So 'Address' would be the hostname. 'Queue' would be"printers/PRINTERNAME".

Once you've added the printer and selected/installed the correct driver, you should begood to go.

If not, there is a setting called 'LogLevel'. By default it's set as follows:

LogLevelwarn

Change it to:

LogLeveldebug

and monitor the log files in /var/logs/cups/error_log for any problems.

So now for the fun part: getting AirPrint to work so users can print from their iPhonesand iPads. There are some great references online, plus a great script to automaticallygenerate the configuration files needed to get your printer advertised by Avahi.

So, Timothy J. Fontaine of Ataraxia Consulting created a python script that automaticallygenerates a .service file for the printers connected via CUPS. You can read hisblog postabout it. The GitHub repository is available here:

https://github.com/tjfontaine/airprint-generate

Anyway, you can (hopefully) download the file directly here:

https://raw.github.com/tjfontaine/airprint-generate/master/airprint-generate.py

First you'll need to install Avahi:

yuminstallavahiavahi-compat-libdns_sd

Then you need to install the Python cups module. For CentOS 6.2, this is, strangely, inthe "system-config-printer-libs" package. So:

yuminstallsystem-config-printer-libs

Then you can run the airprint-generate.py script. Copy the generated .service files into/etc/avahi/services. Then you can start the service:

serviceavahi-daemonstart&&chkconfigavahi-daemonon

I had some trouble with printers not being advertised. Since my local network is on br1instead of eth2 (a KVM thing), I had to add the following to /etc/avahi-daemon.conf:

allow-interfaces=br1

If you had to add that, restart avahi-daemon.

And that's it. Printers should start showing up on your iOS devices.