cups-lpd: Unable to reserve port: Permission denied

[Garry Williams]

I'm copying the list so others can benefit.

On 4/2/07, David Hull <hull at snap.com> wrote:
> Hi.  I saw your post on the web about your CUPS LPD problem.  I've
> recently starting seeing the same issue here.  I have no understanding
> of the underlying problem, but I was able to work around it by changing
> the printer URI from:
>
>         lpd://marengo.pas.lab/milli
>
> to
>
>         lpd://marengo.pas.lab/milli?reserve=none

Thank you for the suggestion.  It worked.

(Actually my URI is lpd://ip-address/?reserve=none .)

I believe that the underlying cause of this problem is a change to the
selinux policy for cups.  I believe that a recent change to the policy
restricts the cups process to only being able to bind to port 631.  (I
can't explain the lack of any avc message when the cups-lpd process
receives an error from bind() due to the policy.)

I don't know whether to call this a bug in the selinux policy or a bug
in cups-lpd.  It seems that there are historical reasons why a
*client* wants or even must bind to a privileged port number.  Anyway,
the work-around you suggest is probably better than modifying the cups
selinux policy.  Most folks never want to access a lpd server.

-- 
Garry Williams +1 678 656-4579