From: William H. Schultz (whschultz_at_[hidden])
Date: 2008-08-04 22:53:59
As the implementer of wxDNSSD (Bonjour for wxWidgets), I can pretty
easily state that Bonjour doesn't need any access to your actual
socket at all. Also, since it uses port 5353, Administrator/root
access is also not needed. Because this is wholly independent of your
actual socket, you can advertise services on any port, whether they
actually exist or not.
I have learned that iTunes--which does not *require* Bonjour be
installed--is statically linked to Bonjour. If Bonjour is installed,
it uses the installed mDNS responder. If not, it runs its own.
http://wxcode.sourceforge.net/complist.php?compperpage=1000&viewmode=full&browseby=category§ion=networking&page=1
http://trac.wxwidgets.org/ticket/9777
-------------------------------
Hank Schultz
Cedrus Corporation
http://www.cedrus.com/
On Aug 3, 2008, at 11:40 PM, Matt Gruenke wrote:
> I know a bit about mDNS, and I think DNS-SD is just a way to
> implement service discovery on top of DNS.
>
> The lookup part of mDNS should be implemented at the system level.
> On a posix system w/ mDNS support, the lookup is normally handled
> transparently via gethostbyname() and therefore requires no special
> support from ASIO. Two ways I've seen this done are via custom
> support in the C library and via a plug-in (specifically, a shared
> library that's specified via /etc/nsswitch.conf). For scalability
> reasons, it is ideal if the lookup consults a daemon process or
> service running on the local machine that can both listen for
> announcements and maintain a cache from which to answer duplicate
> queries.
>
> I think the Windows install of Bonjour has a way of extending the
> normal DNS lookup mechanism to support mDNS, as well. This is
> necessary for use of mDNS from Windows XP, as it lacks built-in
> support. I can't say the same for Windows Vista, however.
>
> I'm not familiar with the other side (i.e. announcements), but I
> wonder whether typical OS security models permit this to be done at
> the application level (i.e. if the user is not running as root or
> local Administrator). If that's the case, then your app would have
> to communicate with a service which supports mDNS announcements for
> that platform - and I'm pretty sure there's no standard way to do
> that.
>
>
> You might find more interest, on the asio-users mailing list:
>
> http://sourceforge.net/mail/?group_id=122478
>
>
> Matt
>
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