Re: Difference between ipp, ipps, http, https CUPS protocols?

[Kent West <westk@acu.edu>]

On 11/12/19 9:02 AM, Brian wrote:
> On Mon 11 Nov 2019 at 10:18:26 -0600, Kent West wrote:
> > > > When adding a printer via the CUPS web interface (localhost:631) on my
> > > > Debian box, Administration / Add Printer / Other Network Printers,
> > > > there are
> > > > four Internet Printing Protocol options:
> > > >
> > > > https
> > > >
> > > > ipp
> > > >
> > > > http
> > > >
> > > > ipps
> > > >
> > > > Which one do I want to select? What are the differences?
> Essentially, use ipp unless you have a good reason not to.

^^^^^^^^^

This is the information I needed, which (IMO) should have been on the 
CUPS setup page.


> Not quite. Both ipp and ipps do encryption. The difference is that ipp
> does oportunistic encryption (using an http upgrade) whereas, with ipps,
> encryption is always on (the encryption is immediate, using https). The
> rationale for having a ipps URI is in RFC7472.
>
> http is the transport protocol for ipp and ipps, and ipp and ipps URIs
> are mapped to http and https URLs. Every modern printer would support
> ipp; in addition, some could support ipps too. I believe the http and
> https backends exist to facilitate connections with Windows machines,
> which historically have lagged far behind in implementing ipp.

And this information helps, too.

Thanks!


--

Kent