Re: [gentoo-user] Re: CUPS and hp OfficeJet Pro

[Mike Edenfield]

On 3/18/2010 3:55 PM, Dale wrote:

> I think avahi is a KDE thing.  I don't really know what zeroconf is.  If
> I recall correctly, some package said it had to have that so I turned it
> on.  No clue what it is even after looking up the definition with euse.
> May as well be Greek.  ;-)

Zeroconf is a set of technologies that are supposed to generate a fully
working IP network with no user or operator intervention.  It includes
three basic parts: link-local network config (e.g. IPv4LL), distribution
hostname resolution (multicast DNS), and automatic service and device
discovery (DNS service discovery).

Used in the context of applications or services, you're usually talking
specifically about the autodiscovery portion, which allows applications
to find services and network devices automatically.  It was primarily
invented at Apple, who developed mDNS and DNS-SD, and is built into OS X
as Bonjour.

Avahi is just a free-software implementation of Bonjour (which was
originally under the not-entirely-free Apple Public License), and from
what I've read has practically overtaken Bonjour in terms of performance
and features.

Back onto the topic at hand: emerging cups with +zeroconf allows it to
respond to service discovery requests.  By default CUPS uses
mDNSResponder, which is Apple's implementation; with +avahi is uses
avahi instead.  This means any Mac on your network will automatically
see CUPS printers, as will any Linux client with avahi properly
installed.  Windows machines with iTunes or Safari installed probably
have Bonjour as well, so they'd also benefit.

On a side-note: CUPS 1.4 stopped supporting Avahi and only supports
Apple's implementation, so the Gentoo devs have disabled zeroconf
support completely until CUPS 1.5 (or whatever) brings back native Avahi
support.

--Mike