Setting up Samba as a Print Server

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Introduction

If you set up Samba as a print server, clients in your network are able to send print jobs to the Samba host using the server message block (SMB) protocol. The examples shown in this documentation use a raw printer in the back end. This configuration requires that the print job is formatted by a driver on the client and thus can be processed by the printer without further processing or filtering.



Supported Print Server Back Ends

Samba supports the multiple print server back ends, such as CUPS and LPRng. For a complete list, see the printing parameter in the smb.conf(5) man page.

For details how to set up the back end, see the print server's documentation.


Samba CUPS or IPRINT Back End Support

When using the CUPS or IPRINT print server back end, Samba must have been built with CUPS support enabled. To verify, enter: 

# smbd -b | grep "HAVE_CUPS"
   HAVE_CUPS

If no output is displayed:



Adding a printer to the Print Server Back End

CUPS

To add a raw printer to an CUPS print server:

  • Open the CUPS admin web interface in your browser. For example, https://servername:631/admin
  • Select the Administration tab and click Add Printer.
  • Select the connection type and enter the corresponding URL to the printer's queue or to the remote print server queue. For example:
  • LPD-based printers: lpd://printer_name/queue
  • IPP (Internet Printing Protocol)-based printers: ipp://printer_name/ipp/port
  • SMB (Server Message Block)-based printers: smb://username:password@domain/windows_print_server_host_name/printer_name
Note that forwarding a job to a print server running Windows Vista or newer, or Windows Server 2008 or newer requires authentication.
  • Enter a name for the printer. This name is used in the smb.conf when sharing the printer using Samba.
  • Select the Raw printer vendor and model.
  • Save the settings.


LPRng

To add a raw printer to a LPRng print server:

  • Add the following line to the /etc/printcap file:
printer_name:sd=/var/spool/lpd/printer_name/:sh:mx=0:mc=0:rm=Printer_DNS_name_or_IP_address
The printer name is used in the smb.conf when sharing the printer using Samba.
For further details about the options used, see the printcap(5) man page.
  • To create the spool directory, enter:
# checkpc -f
  • Restart the LPRng service.



Enabling the spoolssd Service


The Samba spoolssd is a service that is integrated into the smbd service. If you configured Samba as a print server, you can additionally enable spoolssd to increase performance on print servers with a high number of jobs or printers.

Without spoolssd, Samba forks the smbd process or each print job and initializes the printcap cache. In case of a large number of printers, the smbd service can become unresponsive for multiple seconds when initializing the cache. The spoolssd service enables you to start pre-forked smbd processes that are processing print jobs without any delay. The main spoolssd smbd process uses a low amount of memory, and forks and terminates child processes

To enable the spoolssd service:

  • Edit the [global] section in your smb.conf file:
  • Add the following parameters:
rpc_server:spoolss = external
rpc_daemon:spoolssd = fork
  • Optionally, you can set the following parameters:
Parameter Default Description
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 Samba forks this number of new child processes, up to the value set in spoolssd:prefork_max_children, if a new connection is established
spoolssd:prefork_max_allowed_clients 100 Number of clients, a child process serves
spoolssd:prefork_child_min_life 60 Minimum lifetime of a child process in seconds. 60 seconds is the minimum.
  • Restart Samba.

After the restart, Samba automatically starts smbd sub-processes: 

# ps axf
...
30903 smbd
30912  \_ smbd
30913      \_ smbd
30914      \_ smbd
30915      \_ smbd
...

Tuning rpcd-spoolss


By default there is no dcerpc service running at all. You need to connect to a service in order to spawn the process.

If you connect the very first time, then the printers list is not filled up and you need some time till it collects all the information.

This can be time consuming as we need ~1s to get information for a printer from CUPS. If you have more than 50 printers you need to tune it.

Make sure that the idle seconds are bigger than the number of printers connected to CUPS! 

 [global]
   rpcd_spoolss:idle_seconds=300

If it doesn't scale you can increase the number of workers (default=5): 

 [global]
   rpcd_spoolss:num_workers = 10

Enabling the Print Server Support in Samba

To enable the print server support:

  • Set the printing back end in the printing parameter of the [global] section in your smb.conf file. For example:
printing = CUPS
  • Add the following section to your smb.conf:
[printers]
       path = /var/tmp/
       printable = yes
  • Reload Samba:
# smbcontrol all reload-config

Sharing a Printer

Automatic Sharing of All Printers Configured in the Print Server Back End

Using the default setting, all printers configured in the print server back end are automatically shared.


Disabling the Automatic Printer Sharing

To disable the automatic printer sharing:

  • Add the following parameter to the [global] section of your smb.conf file:
load printers = no
  • Reload Samba:
# smbcontrol all reload-config


Manual Sharing of Printers

To manually share a printer:

  • Add the share for the printer to your smb.conf file:
[Samba_printer_name]
       path = /var/tmp/
       printable = yes
       printer name = printer_name_in_the_back_end
Set the printer name parameter to the name of the printer used in the local print server back end.
  • Reload Samba:
# smbcontrol all reload-config



Setting up Automatic Printer Driver Download for Windows Clients

See Setting up Automatic Printer Driver Downloads for Windows Clients.

Known issues

There seems to be an issue with printing after updating Windows 11 to 22H2. Please see this website for more info.

The solution is to edit a Group Policy Object at the computer level under Administrative Templates \ Printers \ Configure RPC connection settings.

  • Set this to "Enabled"
  • Protocol to use for outgoing RPC connections: `RPC over named pipes`
  • Use authentication for outgoing RPC connections: `Default`

If you do not see the settings here, then make sure you either download the Windows 22H2 or later Group Policy Objects from Microsoft's website, or launch the Group Policy Management Console from a computer running Windows 11 22H2 or later.

If needed, the same result can be achived via direct registry editing: 

reg add "HKLM\SOFTWARE\Policies\Microsoft\Windows NT\Printers\RPC" /f /v "RpcUseNamedPipeProtocol" /t REG_DWORD /d "1"
reg add "HKLM\SYSTEM\CurrentControlSet\Control\Print" /f /v "RpcAuthnLevelPrivacyEnabled" /t REG_DWORD /d "0"
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