Setting up Samba as a Print Server

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General

Introduction

This HowTo will provide you an easy guide to setup Samba to act as a Windows print server including Point'n'Click printer driver installation for users.

This HowTo is valid for Samba 3 and 4 print server installations.


Some definitions

Printer share 
Each printer is shared by a name. During the printing process, the client sends the printjob to it.
Print server backend 
Samba can use e. g. CUPS, LPD/Lprng and other as backend. The print server forwards the job to local or network printers.
Windows printer driver 
A piece of software, that converts the printed data to a printer specific form. The driver for each shared printer can be preconfigured with default values.
Point'n'Print 
Windows 2000 and later support the abillity to automatically download and install drivers from the server including preconfiguring, when connecting a printer. The installation can be done by ordinary users, without special permissions.
Printer forms 
Windows is already shipped with an amount of forms, that define the typical paper sizes. If a formular isn't known to the print server, the client could not use this, altought the printer is able to do it.


Driver models

Supported by Samba: Printer driver version 3 (Windows 2000 to Windows 8)

Currently not supported by Samba: Printer driver version 4 (Windows 8)



Print server backend

The following sub-chapters will give you a short overview on possible backends, including adding a new network printer, we'll use in our later examples for sharing it by Samba.

The examples setup a RAW printer (content is send directly to the device). We don't use filters or drivers on the backend, because a RAW printer allows us to render the output on the workstation and use the printer specific driver.

We assume here, that you have the print server backend already basically configured and it's running, so printers can be added next.


CUPS

CUPS is currently the most widely used spool system in *nix environments and shipped with most distributions. Samba has built-in support and defaults to CUPS if the development package (aka header files and libraries) could be found at compile time.

Basically all sorts of files can be printed with CUPS, but using a Postscript or a RAW printer driver will give you the most benefit in combination with the Windows printer driver, because then all settings can be controlled on the Windows client.


Adding a new printer

  • On the „Administration“ tab click the „Add Printer“ button.
  • Choose the way, how your printer is connected and enter the appropriate URL. Examples:
# LPD protocol
lpd://hostname/queue

# Internet Printing Protocol
ipp://hostname/ipp/port

# Forwarding the jobs to a Windows print server.
# Hint: Vista and higher, don't allow anonymous connects by default, so you must provide a username and password.
smb://username:password@domain/servername/printername 
  • Enter a name for the printer
  • When you reached the step, where to choose the vendor and model, choose „Raw“ for both, because the rendering is already done later by the Windows driver.
  • Save the new added printer.


LPD

This was the first widely used printing system and still runs on many servers. It is very simple to install and configure. There are different implementations of LPD servers, like the often used LPRng.


Adding a new printer

  • To add a new network printer, you simply need to add the following line to your 'printcap' (typically '/etc/printcap'). For the different options used in the example, see 'man printcap'.
PRINTERNAME:sd=/path/to/spool/directory:sh:mx=0:mc=0:rm=IP_or_DNS_Name
  • After adding the new printer entry, run the following command to create the LPD spool directory and restart/reload the service, to take the changes affect.
# checkpc -f
# service lpd restart
  • The following command allows you query the state of the printer:
# lpq -P PRINTERNAME
Printer: PRINTERNAME@SAMPRINTSERVER (dest PRINTERNAME@IP_or_DNS_Name)
 Queue: no printable jobs in queue
Ready

no entries



Configuring Samba as print server

General

Enabling spoolssd (optional)

Note: Some features of spoolssd were broken before 4.0.17 and 4.1.7. That's why it is recommended to use at least this versions

spoolssd is a feature, introduced in Samba 4.0, that increases the performance in printing affairs. In the past, when a print job came in, a smbd child process was forked, that initializes the printcap cache, spoolss, etc. If you are having a huge printcap cache and it needs to be updated first, the client could hang for several seconds.

Since Samba 4, you can configure, that spoolssd is started as forked processes. If enabled, you'll see additional smbd processes, which will handle only spoolss requests. The master process is a simple daemon with a small memory footprint, that only forks and kills childs serving the spoolss pipe. When a connection comes in, it can directly start to talk to the daemon and e. g. ask any information about the printer without any delay, what causes a performance improvement.

To enable spoolssd, add the following to your smb.conf:

rpc_server:spoolss = external
rpc_daemon:spoolssd = fork

After you have restarted Samba, you will discover additional smbd processes, that handle spoolss requests:

With spoolssd enabled after startup:       With spoolssd disabled (default):
30903 smbd                                 30955 smbd
30912  \_ smbd                             30963  \_ smbd
30913      \_ smbd
30914      \_ smbd
30915      \_ smbd
30916      \_ smbd
30917      \_ smbd
30918      \_ smbd
30920      \_ smbd
30921      \_ smbd
30922      \_ smbd
30923      \_ smbd
30924      \_ smbd

You can adjust the daemons behavior through the following parameters (the values in the examples are the defaults):

spoolssd:prefork_min_children = 5           # Minimum number of child processes
spoolssd:prefork_max_children = 25          # Maximum number of child processes
spoolssd:prefork_spawn_rate = 5             # Start (fork) x new childs if one connection comes in (up to prefork_max_children)
spoolssd:prefork_max_allowed_clients = 100  # Number of clients, a child process should be responsible for
spoolssd:prefork_child_min_life = 60        # Minimum lifetime of a child process (60 seconds
                                            # is the minimum, even a lower value has been configured)

spoolssd is still a new feature. If you may encounter any bug, please report it at https://bugzilla.samba.org/, to get it fixed soon.


Granting print operator privileges

Users or groups, who should be able to administrate printers on your server, have to be granted the „SePrintOperatorPrivilege“ privilege. This is required on member servers, as they have their own, local SAM database. It is recommended, to grant it to a domain group, because changes can be done quick and easily with the typical user management tools like ADUC.

The following example grants the privilege to the domain group „Domain Admins“:

# net rpc rights grant 'SAMDOM\Domain Admins' SePrintOperatorPrivilege -Uadministrator

Existing privileges you can reviewed by

# net rpc rights list accounts -Uadministrator


Setup the [printers] share

This share defines general information about your printing backend. See the „[printers]“ section in the man page for additional information.

  • Add the new section to your smb.conf
[printers]
     path = /var/spool/samba
     printable = yes
     printing = CUPS|LPRNG|...
  • If you choose CUPS as backend, make sure, that your smbd is compiled with CUPS support:
# smbd -b | grep CUPS
   HAVE_CUPS_CUPS_H
   HAVE_CUPS_LANGUAGE_H
   HAVE_CUPS
   HAVE_LIBCUPS

If you don't get any output, make sure, that the CUPS header files and libraries are installed and recompile Samba with --with-cups.

  • The next step is to create the samba spool directory, defined in the „[printer]“ share. Set the appropriate permissions, depending to your needs.
# mkdir -p /var/spool/samba/
# chmod 1777 /var/spool/samba/


Setup the [print$] share

To enable Point'n'Print support, a share named „print$“ must exist. This share name is hardcoded in Windows clients and can't be choosen.

  • Add the share to your smb.conf
[print$]
     path = /srv/samba/Printer_drivers
     comment = Printer Drivers
     writeable = yes
  • Create the folder, that will contain the drivers later:
# mkdir -p /srv/samba/Printer_drivers/
  • Next we create the required directory structure for the print$ share (newer versions of Samba will create it on the fly):
BASEDIR=/srv/samba/Printer_drivers
for i in COLOR IA64 W32ALPHA W32MIPS W32PPC W32X86/{2,3} WIN40 x64; do 
     mkdir -p $BASEDIR/$i;
done
  • At last, set the permissions. It is recommended that normal users have just read-only access to the share, while the group you have granted print operator privileges to, has write permissions to upload printer drivers. The following examples are granting write permissions to the „Domain Admins“ group.
Example for Samba 3.x:
# chgrp -R „SAMDOM\Domain Admins“ /srv/samba/Printer_drivers/
# chmod -R 2755 /srv/samba/Printer_drivers/
If you're running Samba 4.x, you can set the ACLs on the print$ share, throught Windows. Your benefit would be, that you can use the full Windows ACLs. Have a look at the Setup and configure file shares HowTo. It describes detailed the process, how to set permissions. The suggested filesystem permissions for the print$ share are:
  • Creator Owner: Full control (Subfolders and files only)
  • Authenticated Users: Read & execute, List folder contents, Read (This folder, subfolders and files)
  • System: Full control (This folder, subfolders and files)
  • Domain Admins: Full control (This folder, subfolders and files)


Sharing a printer with Samba

  • For each printer you want to share via Samba, you have to create a separate share (unless you have "load printers = yes" defined in your smb.conf). The following is an example:
[MyDemoPrinter]
     path = /var/spool/samba/
     browseable = yes
     printable = yes
     printer name = Printername_in_backend
  • Set the „printer name“ parameter to the name of your corresponding CUPS/LPD/... queue.
  • To bring the changes live, reload the Samba configuration:
# smbcontrol all reload-config


Uploading printer drivers for Point'n'Print driver installation

If you have already uploaded the driver for your printer in the past, you can skip this section.

Important notes:

  • If you want to provide Point'n'Print support for drivers, used on different architectures (typically 32-bit and 64-Bit Windows), you have to upload a driver with the same name for all that architectures! This is the only way to define the default printer settings just once on a platform of your choice. And when the driver is sent to a host with a different architecture, these default values are used as well. But this requires, that the driver name is exactly the same for each platform. E. g. „HP Universal Printing PS“ for x86 and „HP Universal Printing PS (v5.5.0)“ for x64 would't match, as they are different! Choose exactly the same driver for all platforms, you want to support.
  • Drivers for x64, can only be uploaded from a x64 Windows! Drivers for the x86 architecture can be uploaded from 32- and 64-bit Windows.


The following steps are done on Windows7 64-bit, because 64-bit Windows allows uploading drivers for x86 and x64:

  • Go to \\YourPrintserver and click the „View remote printers“ button
Server Share List.png
  • You will see a list of all printers you have shared.
File:View remote printers.png
  • Right-click somewhere in the empty part of the window and choose „Server Properties...“ from the appearing context menu.
  • Next go to the „Drivers“ tab and click the „Add...“ button. The „Add Printer wizzard will appear.
  • Select the driver architecture you want to upload (upload one by one) and click „Next“.
  • Click the „Have Disk...“ button and browse to the directory containing the driver you want to upload.
  • The wizzard will show you a list of all drivers, the directory you pointed to, contains. Select the appropriate driver for your printer and click „Next“.
Remember: If you upload drivers for additional architectures for one printer, they need all to have exactly the same name! Otherwise the driver can't be associated and used with different platforms!
File:Printer driver selection.png
  • In the end, the wizzard will copy all required files to the print$ share of your print server.
  • If you want to upload drivers for a different plattform or other devices, repeat the steps.


Associating a shared printer with a driver and preconfiguring

  • Go to \\YourPrintserver and click the „View remote printers“ button.
Server Share List.png
  • You will see a list of all printers you have shared.
File:View remote printers.png
  • You could do the association of the driver with the printer share on Windows or on *nix side:
  • On Windows:
  • Right-click to the shared printer, you would associate a driver with and choose „Properties“.
  • If there's no driver associated with an printer yet, you'll been asked if you want to install the driver now. Answer this question with „No“!
File:Question install driver.png
  • A default printer properties window will appear. Go to the „Advanved“ tab and choose the already uploaded driver from the list, that is suitable for the printer.
FAQ: An uploaded driver is not shown in the list, when trying to associate it with a printer.
File:Choose driver.png
  • Close the windows with „OK“ to associate the driver with the printer.
  • If you do this step on Vista or higher, Windows will ask you, if you trust the server (This can be suppressed by a GPO. See Setting up a GPO for trusting printer drivers). Choose „Install driver“, if you are seeing this window.
File:Question trust printer.png
  • After associating the driver, Windows renames the printer to the driver name. You can leave that or rename it again. For more clearness, it's better to set the name on Windows side to the one you used in your smb.conf.
  • On *nix:
  • Retrieve a list of all drivers, that are on the print$ share
    # rpcclient localhost -U administrator -c 'enumdrivers'
  • Associate the driver with the printer (The driver name, must be exactly the same, like in the output of the above „enumdrivers“ output):
    # rpcclient localhost -U administrator -c 'setdriver "MyDemoPrinter" "HP Universal Printing PS"'
  • You can review the associations with
    # rpcclient localhost -U administrator -c 'enumprinters'
  • On Windows, now right-click and choose „Properties“ again, to preconfigure the printer.
  • First you should take a look on the tabs on the properties windows. Typically there's a tab called „Device Settings“, „Settings“, „Configuration“ or something like that (depending on the driver). This usually allows you to configure the main printer settings (number of trays, duplex on/off, etc.). Set the values fitting to your device and click the „Apply“ button.
File:Device Settings.png
  • On the „Sharing“ tab, you can check „List in the directory“, to publish the printer in your Active Directory, what makes it easier for users to find.
  • To preconfigure the printers default settings, go to the „Advanced“ tab and click the „Printing defaults...“ button. A new window will appear. It's layout and possibilities differ and depent on the driver. Here you can set the default values, the user will receive, when connecting the printer.
File:Printing defaults.png
  • If you have finished configuring your printer, save all changes with „OK“.

If you had uploaded drivers for multiple architectures to that printer, the settings will be retrieved connecting on the different plattforms - regardless on which they have been set. But as mentioned earlier, this requires, that all drivers for each plattform have the same name (versions can differ).

Now it's time to connect to the printer and print a test page.



Setting up a GPO for trusting printer drivers

To keep the following guide simple, we setup the policy in the „Default Domain Policy“. If you have different requirements, adapt it to your needs.

  • Open the Group Policy Management console.
  • Go to „Forest: your.domain“ / „Domains“ / „your.domain“
  • Right-click „Default Domain Policy“ and choose „Edit“ to open the Group Policy Management Editor.
File:Edit group policy.png
  • Navigate to „Computer Configuration“ / „Policies“ / „Administrative Templates“ / „Printers“ and double-click to the „Point and Print Restrictions“ Policy (if you want to setup the policy on a per-user base instead of machine-base, go to the same path, but just in the „User Configuration“ branch).
  • Enable the policy and set „When installing driver for a new connection“ and „When updating drivers for an existing connection“ each to „Do not show warning or elevation prompt“. You can restrict the policy in that window to prevent the warning just for defined hosts, too, if required..
File:Point and print restrictions.png
  • Save the changed policy by clicking „OK“ and closing the windows.

After the clients have refreshed their policies (per default every 90 minutes, with a random offset of 0 to 30 minutes), the warning won't be shown up any more. The policy refresh can be forced by

> gpupdate /force /target:computer



Enabling new paper sizes (Forms)

Only standard sizes of formulars are included by default. If you require other forms, you have to add them.

  • Go to \\YourPrintserver and click the „View remote printers“ button
Server Share List.png
  • You will see a list of all printers you have shared.
File:View remote printers.png
  • Right-click somewhere in the empty part of the window and choose „Server Properties...“ from the appearing context menu. The print server forms tab appears.
  • Check „Create a new form“, and fill the values. In the end click „Save Form“, to save your changes.
File:Create new form.png

The new added paper sizes will be selectable from all printer dialogs now.



FAQ

An uploaded driver is not shown in the list, when trying to associate it with a printer

Windows clients only permit associating a driver with a printer, when the uploaded driver matches the architecture reported by the spoolss server. Samba reports "Windows NT x86" by default.

This causes, that when you had uploaded just a 64-bit driver, you won't see it in the list, when you try to associate it with the printer it's „advanced“ tab.

There are three ways to workaround:

  • Set the following (undocumented) parameter in your [global] section of your smb.conf, to make spoolss announce itself as x64 architecture:
spoolss: architecture = Windows x64
  • Assign the driver with rpcclient.
  • Additionally upload a x86 version of the driver with exactly the same name.


Point'n' Print doesn't deliver the drivers on all architectures

Make sure that you have uploaded exactly the same driver for that printer for all architectures. E. g. „HP Universal Printing PS“ for x86 and „HP Universal Printing PS (v5.5.0)“ for x64 wouldn't match, even if they are shipped in the same driver package!