[cups] CUPS + VPN

[Alex Korobkin]

Unfortunately, Bonjour/DNS-SD doesn't always work in the enterprise
environment.

LDAP support or any other way similar to client.conf would be nice to have
as a replacement.

On Thu, Oct 15, 2015 at 2:09 PM, Michael Sweet <msweet at apple.com> wrote:

> Alex,
>
> > On Oct 15, 2015, at 1:41 PM, Alex Korobkin <korobkin+cups at gmail.com>
> wrote:
> >
> > Michael,
> >
> > wrt PS: What does the adoption of this newer API entail exactly?
>
> For applications, it just means using cupsEnumDests instead of
> cupsGetDests.
>
> > Is there a
> > way to use a central print server for multiple Linux clients similar to
> > client.conf approach?
>
> The central server approach still works.  cupsEnumDests uses local queues
> plus those discovered via Bonjour/DNS-SD, so all you need to do share the
> printers from the server and/or maybe configure DNS records (for printers
> that should only be accessible via the VPN).
>
> Longer term we are looking at adding back LDAP support for shared
> printers, but so far we haven't had a lot of requests for that...
>
> > On Thu, Oct 15, 2015 at 8:24 AM, Michael Sweet <msweet at apple.com> wrote:
> >
> >> Lisa,
> >>
> >>> On Oct 14, 2015, at 2:32 PM, Lisa Marie Maginnis <lisam at fsf.org>
> wrote:
> >>>
> >>> Hello,
> >>>
> >>> We are having issues with CUPS and shared printers over our VPN. The
> >> issue is that if a user is not on the VPN when CUPS starts, they are
> unable
> >> to see printers until they restart CUPS by hand. It crossed my mind to
> add
> >> a restart of CUPS to the scripts that run when a client connects to the
> >> VPN, but I wanted to ask around to see if there is a CUPS only solution
> to
> >> try first.
> >>>
> >>> Clients are configured by adding the following line to
> >> /etc/cups/client.conf:
> >>> ServerName printserver.example.com
> >>>
> >>> Is there a way to increase the polling time of the remote cups server?
> >> Or maybe a better way to configure CUPS clients for using a remote cups
> >> server that might not be there when the system first boots?
> >>
> >> The client.conf setting is checked on the startup of every program that
> >> uses the CUPS API (actually for every thread in every program ...)  And
> all
> >> of the standard CUPS programs and APIs will retry both the address
> lookup
> >> and connection to the server.
> >>
> >> So theoretically an application that is started before the VPN is up
> >> *might* not be able to print, but generally speaking that should never
> >> happen unless the program is written explicitly to not retry such
> issues.
> >>
> >> So without more information it is difficult to help you here - what
> >> software isn't working? Where are the printers not showing up?
> >>
> >> ........
> >>
> >> PS: The ServerName directive in client.conf is officially deprecated for
> >> all platforms and explicitly not supported on OS X - sandboxing,
> AppArmor,
> >> SELinux, etc. can all interfere with an application's ability to access
> >> remote servers, so its continued use is not recommended.  Other CUPS
> APIs
> >> (cupsEnumDests in particular) can be used by applications to get a
> dynamic
> >> view of available shared printers (from multiple servers); adoption of
> the
> >> newer (4 years old now) APIs has been slow, however... :/
> >>
> >> _________________________________________________________
> >> Michael Sweet, Senior Printing System Engineer, PWG Chair
> >>
> >> _______________________________________________
> >> cups mailing list
> >> cups at cups.org
> >> https://www.cups.org/mailman/listinfo/cups
> >>
> >
> >
> >
> > --
> > -Alex
> > _______________________________________________
> > cups mailing list
> > cups at cups.org
> > https://www.cups.org/mailman/listinfo/cups
>
> _________________________________________________________
> Michael Sweet, Senior Printing System Engineer, PWG Chair
>
> _______________________________________________
> cups mailing list
> cups at cups.org
> https://www.cups.org/mailman/listinfo/cups
>



-- 
-Alex