[ntp:questions] zeroconf for ntpd?

David L. Mills mills at udel.edu
Tue May 22 18:42:59 UTC 2007


Wolfgang,

"Will this work?" It does work. It's called manycast and has been 
working with some refinements for several years.

Dave

Wolfgang S. Rupprecht wrote:
> I just watched a Google Talk series video about Bonjour, their
> zero-configuration hack.  Basically they use link-level multicasts to
> figure out who is out on the local net and who can do what.  They even
> go so far as assigning IP addresses and hostnames via this cloud of
> participating hosts.  Getting away from having users edit config files
> (after reading a half dozen man pages) seems like a good thing.
> 
> It looks like quite a bit of work went into making ntpd do some of the
> same things. Now that multicast no longer binds to only the first
> interface it finds, it looks like it may almost be possible to deliver
> an ntp config file that "just works" yet doesn't beat up the pool
> servers too much.
> 
> Can folks help me flesh this out?  Will this work?
> 
> /etc/ntp.conf:
> 
>     restrict default nomodify notrap nopeer
>     restrict 127.0.0.1 
>     restrict -6 ::1
>     broadcast ff02::101             # ipv6 link-local multicast
>     broadcast ff05::101             # ipv6 site-local multicast
>     broadcast 224.0.1.1     ttl 1   # ipv4 multicast
>     orphan 5
>     multicastclient ff02::101       # ipv6 link-local multicast
>     driftfile /var/lib/ntp/drift
> 
> plus on the first 2 hosts only:
> 
>     server 0.fedora.pool.ntp.org dynamic
>     server 1.fedora.pool.ntp.org dynamic
>     server 2.fedora.pool.ntp.org dynamic
> 
> Any bright ideas of figuring out quickly if the cloud needs to grow a
> few external connections?  The big hammer seems to be to parse the
> 'ntpq -pn' output with a shell script and then add the pools servers
> at runtime if nobody in the cloud has any external pool links yet.
> 
> Ideas? Comments?
> 
> -wolfgang




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