My /dev/lp0 has the following permissions set (correctly): crw-rw---- 1 root lp 6, 0 Feb 8 2008 /dev/lp0 In /etc/cups/cupsd.conf, I defined: User lp Group lp When I try to print, I get the error: E [05/Feb/2008:03:30:24 +0100] [Job 1104] Unable to open parallel port device file "/dev/lp0": Permission denied As /usr/libexec/cups/filter/foomatic-rip is a perl-script, I added a simple 'id' and I got this: uid=4(lp) gid=65534(nobody) groups=65534(nobody) It seems that CUPS doesn't set the group correctly. I remember roughly that this error is already really old, at least I have seen the missing group setting once in an earlier version. I am using cups 1.2.12-r4.
The same problem occurs in CUPS 1.3.5.
*** This bug has been marked as a duplicate of bug 137795 ***