Problems with ntp4.2 when names resolve to IPv6 addresses

[David Malone]

On Tue, Jul 27, 2004 at 11:46:31PM +0200, Brad Knowles wrote:
> At 6:20 PM -0700 2004-07-25, Kevin Oberman wrote:
> > I did not notice any problem while I was on an IPv6 connected network at
> > work or while on travel at a networking conference as they have IPv6
> > connectivity, but when I tried from home, where my broadband provider
> > does not provide any IPv6 routing, ntp simply spits out messages that it
> > failed to connect to each server.

> 	This may be a bug with the base code from ntp.org.  We'd want to 
> know more about this particular problem.  Can you file a bug at 
> bugzilla.ntp.org?

Ntpd has some issues in this area. It will always try the first
address returned by getaddrinfo and doesn't fall back to other
addresses if things don't work out. This means if you don't have
IPv6 connectivity, but your server does have an AAAA record, then
you probably won't be able to talk NTP to the server. The fix is
to change ntp.conf to say "server -4 server.name" rather than just
"server server.name".

(The same problem exists with servers with multiple IPv4 addresses,
some of which are unreachable, it's just less obvious...)

	David.