Bug 142411

Summary: nss-mdns provides link-local mDNS hostname lookups
Product: [Fedora] Fedora Reporter: Will Woods <wwoods>
Component: distributionAssignee: Bill Nottingham <notting>
Status: CLOSED DEFERRED QA Contact: Bill Nottingham <notting>
Severity: medium Docs Contact:
Priority: medium    
Version: 3CC: aleksey, drepper, rvokal
Target Milestone: ---Keywords: FutureFeature
Target Release: ---   
Hardware: All   
OS: Linux   
URL: http://0pointer.de/lennart/projects/nss-mdns/
Whiteboard:
Fixed In Version: Doc Type: Enhancement
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Clone Of: Environment:
Last Closed: 2005-03-02 22:35:20 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description Flags
a specfile for nss-mdns none

Description Will Woods 2004-12-09 16:42:33 UTC 
Fedora already ships with mDNSResponder (part of howl) which can
respond to mDNS queries. That corresponds to the server portion of a
normal DNS setup. nss-mdns is an NSS plugin that adds the
corresponding client code to glibc.

With this package installed and configured properly (all I had to do
was add 'mdns4' to the hosts: line in nsswitch.conf) machines can
refer to each other by name even in the absense of a DNS server,
either with valid DHCP-assigned IP addresses or self-assigned
(Zeroconf/IPv4LL) addresses. I've tried it with two linux boxes and a
Mac, both on a private and public network.

This feature is a part of Apple's Rendezvous technology (giving better
Mac interoperability) and would also make running home/small office
networks a lot easier (no DNS server needed! Plug in a new machine or
a laptop and instantly refer to it by its name!)
Comment 1 Will Woods 2004-12-09 16:45:25 UTC 
Created attachment 108226 [details]
a specfile for nss-mdns

I guessed on the Group. It doesn't modify nsswitch.conf, but I don't know how
that should be done.
Comment 2 Bill Nottingham 2004-12-09 17:30:23 UTC 
authconfig is normally what modifies nsswitch.conf.

Want to maintain nss-mdns? >:)
Comment 3 Bill Nottingham 2005-03-02 22:16:57 UTC 
Uli, is there planned to be any mDNS work in glibc directly that would conflict
with this, or is a new nss module the way to go?
Comment 4 Ulrich Drepper 2005-03-02 22:24:21 UTC 
The approach taken by the current nss-mdns is wrong.  The problem is that the
broadcasted results are not used.  The result is that the network is flooded
with unnecessary requests.

I talked to the author some time back and he acknoledged this.  He said he is
currently writing a program similar to the nDNSresponder which then will also
listen for the broadcast traffic and be able to answer requests from the
nss-mdns module.

Without this functionality the nss-mdns module is dangerous if you have more
than a couple of machines.

I'm not sure whether I trust the author to make all the changes in a timely
manner.  If not, I'll add appropriate code myself.  Until it is resolved one way
or another, we should not provide any half-cooked mdns support.
Comment 5 Bill Nottingham 2005-03-02 22:35:20 UTC 
OK. Deferring, then.