Why Are the CUPS LPR Commands Not SETUID Root?

The LPD protocol forces clients to reserve a priviledged port to send print files. Since priviledged ports require root access, the lpr, lpq, lprm, and lpc programs are setuid root.

The CUPS software uses the IPP protocol which does not have this requirement. Therefore, all LPR client programs can be regular executables (no setuid to root) which poses fewer security risks.