Adding a printer

1. IP Registration
2. Two ways to drive a printer
3. What does a printer support?
4. Queue name
5. Who can print?
6. The information you must pass us

IP Registration

First of all, a networked printer must be registered for an IP address and a DNS name. This is quite orthogonal to getting its print queues registered. It's a network device and needs a network identity.

You should contact ip-register@ucs.cam.ac.uk detailing the following points.

• That a name and address are required.
• The institution the printer is within.
• The location at which the printer will be connected.
• The type of printer.
• A contact for the printer, should things go wrong. Name and email address, please.
• A suggested name for the printer.

The suggested name for the printer should not be the same as the queue name, as this permits a degree of future flexibity in moving a queue from one printer to another.

Two ways to drive a printer

There are two ways of driving your printer directly that we support.

• The first applies if your printer supports an LPD interface itself. We can send print jobs directly to it, but you are unlikely to get error messages emailed back to you with this set up. In this case the printer typically provides two LPD queues. One is called "text" and printing to it triggers plain text ("typewriter") printing. The second is called "raw" and it will interpret PostScript sent to it. It is typically this second queue that is more use. We can set up two queues on lpd-serv.cam.ac.uk, one for each.
• The second involves the "JetDirect" interface which, despite its name, applies to more than just HP LaserJets. This sort of printer listens on a particular network port (typically 9100) and lpd-serv.cam.ac.uk interprets the print job and communicates directly in PostScript with the printer via that port. In this case our server interprets any PostScript errors and emails them back to you.

What does a printer support?

To determine what interfaces your printer supports, you can either read the copious technical documentation that comes with it (if only) or look at the probing data. Look at the raw data for the "miscellaneous services" for your printer. Port 515 is the LPD service and port 9100 is the JetDirect service. Many printers support both interfaces.

    Port        State   Service
    515/tcp     open    printer
    9099/tcp    open    unknown
    9100/tcp    open    jetdirect

If the probing output says that all ports were closed then you have a printer that has been configured to restrict who can access it. So long as that access list contains lpd-serv.cam.ac.uk this won't interfere with the setup, but it does stop the probing suite from investigating it for you.

Queue name

Regardless of how you drive the printer, we will have to agree on the queue name lpd-serv.cam.ac.uk uses for the printer. There are a number of constraints on queue names which we impose to make the queue name acceptable over as wide a range as possible of Unix printing systems.

• The name must have 14 or fewer characters.
• The name must be composed of lowercase letters, digits and underscores.
• There must be no adjacent underscores.
• The queue name must be of the form <prefix>_<suffix>.
• The prefix must be fixed for your institution and must not contain underscores. Here are some examples:
  • cs: Computing Service
  • jims: Judge Institute of Management Studies
  • kings: King's College
  • phy: Department of Physics
  • ul: University Library
  • admin: MISD, Old Schools
  • chem: Department of Chemistry
• The suffix is entirely your choice and may contain underscores.

Who can print?

We cannot maintain a list of approved systems that may print to an attached printer. If you allow your printer to receive print jobs from lpd-serv.cam.ac.uk you are trusting everyone we trust. We do, however, maintain logs of all print jobs. If you find your printer is being abused we can help track down who is submitting the print jobs if they came via our system. Contact, as ever, unix-support@ucs.cam.ac.uk detailing the print queue an approximate time and some idea of the nature of the abuse of the printer.

Within UCS, lpd-serv.cam.ac.uk generates the printer configuration files for all the queues known about. If (and only if) you ask us, we will add the queue for your printer to the queues known about by Hermes. In addition, while we do not directly manipulate the CAPSA printing database, if you ask that the print queue be known to CAPSA we will deal with the transmission of the relevant data to the CAPSA group. The print queue name on CAPSA will now be the same as the one we rgister because the CAPSA departmental prefixes are unique to CAPSA.

The other "Who can print?" issue is to restrict who has network access to the printer. The instructions for how to make this restriction will clearly depend on the type of printer.

Configuring an HP LaserJet printers networking by BOOTP

As far as the author can tell, it is only possible to set up network access restrictions on an HP LaserJet if you configure the printer using what the printer calls the RARP/BOOTP/TFTP configuration model.

Other printers

I've been promised some information by the MISD about how they configure their Lexmark printers. (2000-07-28)
If anyone has analogous information for other styles of printer or suggested iomprovements to the existing procedure(s) then please contact unix-support@ucs.cam.ac.uk with details.

The information you must pass us

For each printer you will need to give us the following information.

• DNS name of the printer
• Administrative contact in case of difficulties
• The queue name to use on lpd-serv.cam.ac.uk
• Type of printer
• Mechanism for printing (LPD to printer, PostScript to printer)
• Local queue name (for LPD to printer)
• The systems you want us to enable printing from. (All, some or none of the CUS, Thor, Hermes and CAPSA)
• Your CAPSA departmental ID if you want the queue accessed from CAPSA.