MDNS backchannel on OSX 10.4

Michael R Sweet msweet at
Thu Sep 18 22:08:22 PDT 2008

keens312 wrote:
>> keens312 wrote:
>>>> keens312 wrote:
>>>>> Hi Michael,
>>>>> I check all the CUPS version, only latest 1.4 version contains mdns backend.
>>>>> But OSX 10.3 and 10.4 has released for years, where does OSX 10.3.9 and 10.4 get the mdns backend from?
>>>> Mac OS X 10.5 and earlier use a different mdns implementation that was
>>>> not open sourced.  That said, all the mdns backend does when printing
>>>> is execute the backend that corresponds to the protocol being used -
>>>> ipp, lpd, riousbprint, or socket.  Any back-channel support will come
>>>> from those backends and not mdns itself.
>>>> --
>>>> ______________________________________________________________________
>>>> Michael R Sweet                        Senior Printing System Engineer
>>> what exact backend does Bonjour use? from CUPS log, i only knew mdns backend was launched.
>> Like I said, that depends on the advertised protocol:
>>      Protocol           Backend
>>      -----------------  -------
>>      pdl-datastream     socket
>>      printer            lpd
>>      ipp                ipp
>>      riousbprint        riousbprint
>> --
>> ______________________________________________________________________
>> Michael Sweet, Easy Software Products           mike at easysw dot com
> Hi Michael,
> We must get the status message from printer and display it in the UI on OSX 10.4.
> What do you suggest?
> I am thinking about create a thread in filter, and keep read TCP data from network printing port directly.
> Is this feasible?

No, it is not feasible.  It isn't even possible unless your devices
have an alternate port/channel that can be query separately from
the print channel.  Even so you'll have to resolve the service name
in order to get the address being used...

Michael R Sweet                        Senior Printing System Engineer

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