Portmap against cups

Boris Vinarsky borisv at rambus.com
Thu May 29 10:28:32 PDT 2008

> Boris Vinarsky wrote:
> > We noticed that occasionally CUPS service fails to start on our RHEL4 desktops because port 631 was busy. The reason was that portmapper service which selects ports in the range 600-1023 essentially randomly would assign ports 631 to ypbind or nfs.lock which start before cups.
> >
> > This issue is discussed at https://bugzilla.redhat.com/show_bug.cgi?id=103401
> >
> > Does anybody have a good idea on how to resolve this collision?
Thank you for your suggestions.

> Start cups before portmap?
See comment #13 https://bugzilla.redhat.com/show_bug.cgi?id=103401#c13
In a nutshell if cups starts before services using portmap, and portmap assigns port 631 to one of these services it will not start. Imagine NIS not starting because cups is occupying port assigned to it.

> Fix portmap to not use well-known privileged ports?
This sounds good, just requires to reconfigure massive number of hosts on different platforms, and to pray that nothing in cups is hard coded for port 631. If Linux vendor decides to patch cups there is a good chance that config file will be replaced without honoring the port change. I wonder why this port was selected in a first place considering that it may collide with NFS, NIS, and other security sensitive services. Until I know the reason I am reluctant to change the port number.
> --
> ______________________________________________________________________
> Michael R Sweet                        Senior Printing System Engineer

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