5.8. Force Connection to Localhost

Options used:

• force_localhost FLAG force localhost to be remote host

The legacy BSD print spooler required an lpd print server to be running on each host. During the initial stages of development and deployment, the default LPRng configuration and deployment was to always allow lightweight operation, that is, clients would always connect to the remote host specified in the printcap.

While this default was appropriate for experienced system administrators, novice administrators or those who had already configured print spooling systems and simply wanted to upgrade found themselves confused by this change. This problem resulted in over 700 postings to the LPRng mailing list in a five year period.

This problem was solved by providing a force_localhost option in the configuration, and setting the default value to 1 or TRUE. When this option is TRUE, then all LPRng clients will connect to the server on the localhost, unless they use the lpr -Pserver@host command line form. If lightweight operation is wanted, the administrator can either compile the LPRng software with the appropriate value or can explicitly set the force_localhost@ flag.

    # default:
    lp:lp=lp@10.0.0.1:...
      lpr -Plp ->
        lp:lp=lp@localhost:...
      lpr -Plp@10.0.0.1 ->
        lp:lp=lp@10.0.0.1  (no other options)
    
    lp:lp=lp@10.0.0.1:force_localhost@:...
      lpr -Plp ->
        lp:lp=lp@10.0.0.1:...
    
    To disable at compile time:
      configure --disable-force_localhost