Setup and Configuration II
CUPS does not only allow access to local printers, but also to all kinds of
remote printers. Except for CUPS printers in the local network, you have to
choose a machine in your local network to install a queue for the remote
printer on. This machine broadcasts the information about the remote printer
to all the other machines in the local network (assuming that they run the
CUPS daemon and the broadcasting of the queue machine is not restricted). So a
remote printer needs to be installed only once in a local network.
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CUPS or IPP server
If you have a simple network with shared Internet access (Internet access
through one server) at home or in a small office, you should also take a look
at the "Small network" example.
The simplest scenario is if the remote printer you want to use is hosted by
another machine in your local network running the CUPS daemon. If
there are no access or broadcasting restrictions configured on the remote
machine with the printer, it will broadcast the information of the printer to
your machine every 30 seconds and so the printer gets automatically detected
by your machine within 30 seconds after starting your local CUPS daemon. If
the remote server goes down or the printer is removed, the appropriate queue
on your local machine will disappear within 5 minutes. So you do not need to
configure anything, and you do not need to restart the CUPS daemon.
This broadcasting only works when all your CUPS servers and CUPS clients
are in the same local network.
The "same local network" means that the IP addresses are the same in all the
fields where the Netmask is set to '255', for example:
Server: 192.168.1.34, Client: 192.168.1.94, Mask: 255.255.255.0
Server: 132.180.23.40, Client: 132.180.97.83, Mask: 255.255.0.0
Whereas in this case server and client are not in the same local
network:
Server: 133.181.93.68, Client: 133.181.1.95, Mask:
255.255.255.0
In this case the broadcasting does not work. If you want to print on all
the printers which the server in this example knows of, you have to add the
line
BrowsePoll 133.181.93.68:631
to your '/etc/cups/cupsd.conf' file. If you want that these printers are
available to your whole local network and not only to the machine where you
have added the BrowsePoll line, add the line
BrowseRelay 127.0.0.1 255.255.255.255
Restart the CUPS daemon with:
service cups restart
Alternatively, you can use 'kupsdconf' and enter the name or IP of the
server in "Browsing"/"Connection"/"Poll addresses". You can enter more than
one server for polling its printer information.
Instead of polling the printer information through the client, you can also
tell the server's CUPS daemon that it should broadcast the printer information
to the network you desire. Leave the '/etc/cups/cupsd.conf' file on your
client alone and add the lines
BrowseAddress [Broadcast IP for 1st network]
BrowseAddress [Broadcast IP for 2nd network] ...
to the '/etc/cups/cupsd.conf' of the server. In our example networks you
should add:
BrowseAddress 133.181.93.255
BrowseAddress 133.181.1.255
The broadcast addresses of your networks can be determined by entering
ifconfig
on a machine in the appropriate local network and looking for a "Bcast"
entry. Restart the CUPS daemon on the server with
service cups restart
or use "Browsing"/"Connection"/"Broadcast addresses" in 'kupsdconf'.
Another important point is that every machine with a printer made available
by CUPS needs a defined name. This name must be known to the clients and be
used in the information broadcast into the network. The print server must have
a fixed IP for the local network and not a dynamic one. You can set its name
with 'Linuxconf' choosing "Networking" and then "Host name and IP network
devices". In the upcoming dialog click on the tab for the network interface
for your local network. Fill in the "Primary name + domain" field with the
desired name, for example "server.localdomain". Do not keep the name
"localhost" or "localhost.localdomain" here.
To get the chosen name broadcast, add a line
ServerName [server's name]
to the '/etc/cups/cupsd.conf' file on the server and restart the CUPS
daemon with
service cups restart
In 'kupsdconf', go to the "Server" section and fill in the "Server name"
field with the server's name.
If the clients cannot resolve that name (e.g. due to lack of DNS), add an
appropriate entry (one per server) to the '/etc/hosts' file on the
clients:
[servers's IP] [server's name].[domain] [server's name]
for example
133.181.93.68 server.localdomain server
Note: By this method you always get all printers and classes of
the remote server, you cannot choose individual printers.
Important: If a machine in local network has two different IPs,
one for the local network (192.168.1.x) and a completely different one for
'outside' (e.g. the Internet), it is possible that CUPS uses the outside
address. In this case broadcasting will not work.
Use the BrowsePoll line on the client or the
BrowseAddress line on the server. In both cases the correct
server name for the local network must be set in the ServerName
line of '/etc/cups/cupsd.conf' on the server. See the "Small network" example.
If you do not want all the printers from the CUPS server in the remote
network being visible on your client or if you want to have the queues for the
printers of the remote CUPS servers being broadcast in your local network, you
can install selected queues on your client:
Enter the web interface of CUPS (http://localhost:631/printers/) and
click on "Add Printer" at the end of the page. Enter name, description, and
location for the queue, choose the second entry for "Internet Printing
Protocol" on the device page. On the next page, enter:
ipp://[server name or IP]/printers/[name of the printer on the
server]
So if your server's name is "paperwaster" and it has a printer named
"laserjet", you enter:
ipp://paperwaster/printers/laserjet
Afterward choose the appropriate manufacturer and model and your queue for
the printer in the remote network is ready.
You can do this on the command line, too:
lpadmin -p [local queue] -E -v \
ipp://[server]/printers/[printer on server] -m [PPD file]
CUPS uses the Internet Printing Protocol (IPP) for communication between
the daemons on the machines on a network. There are also some
Ethernet-connected printers which use IPP. They behave like a remote CUPS
server, but the default configuration (broadcasting, access, ...) can be
completely different. Check the printer's web interface (http://[printer
name or IP]/ or http://[printer name or IP]:631/).
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LPD server
LPD (Line Printer Daemon) servers are very common, because LPD is the
default printing system of every other Linux distribution and in every
commercial Unix. It is also used by some Ethernet-connected printers (as
Tektronix Phaser) and one can
configure Windows NT servers to make their printers available via LPD.
All which is needed for this form of access is already in the CUPS package,
so you do not need to install additional packages. In 'PrinterDrake' you
choose "Add", then "Remote Printer" and afterward "Remote lpd server". After
entering the name, description, and location, you will be asked for the host
name of the server and the name of the printer queue on the server (on most
Ethernet connected printers and printing server boxes the queue name is "lp",
"lpr", or "lpd", on a Tektronix Phaser also "PS"). Afterward you choose the
driver like for a local printer and you are set.
In 'Kups' you choose "Printer"/"Add" and in the wizard you choose "LPD".
Then you enter the server's name and the name of the queue on the server,
afterward the rest of the information like for a local printer. You cannot
enter a wrong queue name, 'Kups' checks the name which you have entered. After
clicking on "Add printer" on the web interface and entering the queue name,
you choose "LPD/LPR Host or printer" on the page for selecting the device. On
the next page you enter:
lpd://[server name]/[queue name on server]:
Afterward you select the driver as usual.
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AppSocket network
printer
The AppSocket protocol is only used by Ethernet-connected printers or
printing server boxes (e. g. HP JetDirect). In 'PrinterDrake', you choose
"Add", "Remote Printer", and "Network printer (socket)". Later on you will be
asked for the printer's host name and a port. You only need to enter the port
when it is not the default (9100).
In the wizard for adding printer queues in 'Kups', choose "Socket" and on the
next page "Scan" and after some seconds you get a list of all AppSocket
printers in your local network. If you want to access a printer with a port
other than 9100 or in a remote network, change the scope of the scanning
process with the "Settings" button or enter host name and port for the desired
printer manually.
In the web interface of CUPS you have to choose "AppSocket/HP JetDirect" as
the device. Enter
socket://[hostname]
or
socket://[hostname]:[port]
on the next screen.
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Windows server
To use a printer on a Windows server, CUPS has to work as an SMB client. To
be able to do so the "samba-client" package must be installed (urpmi
samba-client).
When the Samba client package is there, the choice "SMB" in the printer adding
wizard of 'Kups' will be available. Simply choose it, enter the login and
password for your Samba server (or use the guest access) and click on "Scan
network ..." on the next screen. Click on the + on the left of
the name of your workgroup and then double-click the name of your server to
get a list of the provided printers. Choose the printer and go on like for a
local printer.
In 'PrinterDrake', you choose "SMB/Windows 95/98/NT" after you have clicked on
"Add" to install a new printer. After entering the queue name you are asked
for the server name and IP, user name and password, the share name, and the
workgroup. Except for user name and password all fields have to be filled out.
Leaving out user name and password means that you access the printer via a
guest account. The share name is the name of the printer on the Windows
server. It is not recommended to use the web interface or 'lpadmin' to set up
the access to a Windows printer, since you have to enter the password in clear
text in both.
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