lpsystem -- register remote systems with the print service


lpsystem [-t type] [-T timeout] [-R retry] [-y "comment"] system-name
[system-name . . . ]
lpsystem -l [system-name . . . ]
lpsystem -r system-name [system-name . . . ]
lpsystem -A


The lpsystem command is used to define parameters for the LP print service, with respect to communication (via a high-speed network such as TCP/IP) with remote systems. Only a user with appropriate privileges may execute the lpsystem command.

Specifically, the lpsystem command is used to define remote systems with which the local LP print service can exchange print requests. These remote systems are described to the local LP print service in terms of several parameters that control communication: type, retry and timeout. These parameters are defined in /etc/lp/Systems. You can edit this file with a text editor (such as vi) but editing is not recommended. By using lpsystem, you can ensure that lpsched is notified of any changes to the Systems file.

The type parameter defines the remote system as one of the following types:

System V Release 4

The default type is s5.

The timeout parameter specifies the length of time (in minutes) that the print service should allow a network connection to be idle. If the connection to the remote system is idle (that is, there is no network traffic) for N minutes, then drop the connection. (When there is more work the connection will be re-established.) Legal values are n, 0, and N, where N is an integer greater than 0. If a decimal number is used for N, it will be truncated to the whole number. The value n means ``never time out''; 0 means ``as soon as the connection is idle, drop it.'' The default is n.

The retry parameter specifies the length of time (in minutes) to wait before trying to re-establish a connection to the remote system, when the connection was dropped abnormally (that is, a network error). Legal values are n, 0, and N, where N is an integer greater than 0 and it means ``wait N minutes before trying to reconnect. If a decimal number is used for N, it will be truncated to the whole number. (The default is 10 minutes.) The value n means ``do not retry dropped connections until there is more work''; 0 means ``try to reconnect immediately.''

The comment argument allows you to associate a free form comment with the system entry. This is visible when lpsystem -l is used.

system-name is the name of the remote system from which you want to be able to receive jobs, and to which you want to be able to send jobs. Two special entries are provided with the /etc/lp/Systems file by default. These entries allow all connections to s5 and bsd systems. The entry that allows connection to any s5 system uses the plus sign (+) as the system-name. The entry that allows connection to any bsd system uses the asterisk (*) as the system-name.

The command lpsystem -l [system-name] will print out a description of the parameters associated with system-name (if a system has been specified), or with all the systems in its database (if system-name has not been specified).

The command lpsystem -r system-name will remove the entry associated with system-name. The print service will no longer accept jobs from that system or send jobs to it, even if the remote printer is still defined on the local system. The scheduler must be running when the removal of a systems file entry occurs, because the scheduler checks whether the system entry is currently used by a printer destination. If currently used, the system entry cannot be removed.

If you use lpsystem -r system-name to remove a system and you have active printers for that system, you will not be allowed to remove the system from the system file. lpsystem -r system-name will only work if no printers for that system exist.

The command lpsystem -A will print out the TCP/IP address of the local machine in a format to be used when configuring the local port monitor to accept requests from a SunOS system.



language-specific message file (see LANG on environ(5)).





Network addresses and services are handled by the Name-to-Address Mapping facilities. (See the ``Network Services'' chapter in the Network Administration for a discussion of network addresses and services.) Port monitors handle listening for remote service requests and routing the connection to the print service.

If the Name-to-Address Mapping facilities are not set up properly, out-bound remote print service probably will not work. Similarly, if the local port monitors are not set up to route remote print requests to the print service, then service for remote systems will not be provided.

With respect to the semantics of the timeout and retry values, the print service uses one process for each remote system with which it communicates, and it communicates with a remote system only when there is work to be done on that system or work is being sent from that system.

The system initiating the connection is the ``master'' process and the system accepting the connection is the ``slave'' process. This designation serves only to determine which process dies (the slave) when a connection is dropped. This helps prevent there from being more than one process communicating with a remote system. Furthermore, all connections are bi-directional, regardless of the master/slave designation. You cannot control a system's master/slave designation. Typically, a client machine has the master child and the server machine has the slave child. Now, keeping all this information in mind, if a master process times out, then both the slave and master will exit. If a slave times out, then it is possible that the master may still live and retry the connection after the retry interval. Therefore, one system's resource management strategy can affect another system's strategy.

With respect to lpsystem -A: a SunOS system (described with -t bsd) can be connected to your system only via TCP/IP, and print requests from a SunOS system can come in to your machine only via a special port (515). The address given to you from lpsystem will be the address of your system and port 515. This address is used by your TCP/IP port monitor to ``listen'' on that address and port, and to route connections to the print service. (See sacadm(1M) and nlsadmin(1M).) The important point here is that this is where you get the address referred to in that procedure.

The command lpsystem -A will not work if your system name and IP address are not listed in /etc/inet/hosts and the printer service is not listed in /etc/inet/services.

All forms of the lpsystem command accept + or ``*'' (asterisk enclosed in double quotes) for system-name.

For the bsd print protocol, an extra configuration option is supported, but only via the /etc/lp/Systems file. On a printer server, it is possible to allow the root user on a remote client to cancel requests originating with any other client. See cancel(1). As this may not be a desirable feature in all environments, it is disabled by default. To enable, close down the print services, using lpshut(1M), and edit /etc/lp/Systems, replacing the hyphen (-) in column 5 with a ``t'', for those bsd clients marked as ``trusted''. After saving the file, restart the print services using lpsched(1M).

Note that, depending upon the configuration of the name server, you may need to change the entry in the ``System-name'' field in /etc/lp/Systems to a full domain name.

© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 25 April 2004