Unable to reserve port: Permission denied

CK f_u_2_2001 at yahoo.com
Sat Mar 31 16:40:36 PDT 2007


> > Hi,
> >
> > I used to be able to print via CUPS previously but recently after a recent automatic update by yum-updatesd, I cannot print anymore. Instead, when I look into the file /var/log/cups/error_log, I get the error message:
> > Unable to reserve port: Permission denied. I try to delete and define the printer again but still it could not print.
> >
> > My printer is connected via parallet port to an SMC Barricade Broadband router which also acts as a LPD print server. I have another PC running windows and I have no problem problem printing to the printer from that PC via the same SMC Barricade router. There has been no change in any hardware or network settings.
> >
> > I am using Fedora Core 6 kernel 2.6.20-1.2933.
> >
> > The various CUPS RPM installed are:
> > libgnomecups-0.2.2-8
> > cups-1.2.7-1.8.fc6
> > hal-cups-utils-0.6.5-1.fc6
> > cups-libs-1.2.7-1.8.fc6
> >
> > Please help. Thanks.
>
>
> This is not a CUPS bug.
>
> Some other process is stealing port 631 (unless you configured CUPS to use a non-standard port) before cupsd can get it. 631 is a "well-known" port, reserved by IANA for IPP (Internet Printing Protocol).
>
> To find out which process that is, try this command:
>
>     lsof -i :631 | egrep -i '(UDP|LISTEN)'
>
> The "name service caching daemon" nscd is known to sometimes behave like that on some systems.
>
> A potential fix would be to change the order the daemons are started up on your system to make sure cupsd can get its port before any other service occupies it.
>
> A quick'n' dirty workaround could be to give CUPS a different port (like 10631) on your local system; but this is only adviceable if your system is self-containing as far as printing is concerned (if it does not share out its printer to other workstations, and if it does not use an external print server ["printer browsing"] -- otherwise you'd have to change these systems as well).


Thanks for replying. However, when I execute the command to see which process is using port 631, it shows that cups is using it, as shown below:

[root at prosper ~]# ps -ef | grep nscd
root      4044  4019  0 07:33 pts/1    00:00:00 grep nscd
[root at prosper ~]# lsof -i :631 | egrep -i '(UDP|LISTEN)'
cupsd   2712 root    3u  IPv4   9725       TCP localhost.localdomain:ipp (LISTEN)
cupsd   2712 root    4u  IPv6   9726       TCP prosper:ipp (LISTEN)
cupsd   2712 root    6u  IPv4   9729       UDP *:ipp





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