bin/44688: ntpd tries to use unusable IPv6 addresses

[martin%NetBSD.org@localhost]

>Number:         44688
>Category:       bin
>Synopsis:       ntpd tries to use unusable IPv6 addresses
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Mar 05 18:30:00 +0000 2011
>Originator:     Martin Husemann
>Release:        NetBSD 5.99.47
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD night-owl.duskware.de 5.99.47 NetBSD 5.99.47 (NIGHT-OWL) #28: 
Sat Feb 26 13:10:46 CET 2011 
martin%night-owl.duskware.de@localhost:/usr/src/sys/arch/amd64/compile/NIGHT-OWL
 amd64
Architecture: x86_64
Machine: amd64
>Description:

I have a ntpd server that has both IPv4 and IPv6 addresses. On a client machine
I use a GENERIC kernel but have no IPv6 setup. The ntp.conf file on that
client points to the ntpd server via it's hostname.

The client, obviously, can only contact the server via IPv4, any try to
send IPv6 of course fails with "no route to host". Nevertheless ntpd never
contacts the server and seems to use the local IPv6 adress:

     remote           local      st poll reach  delay   offset    disp
=======================================================================
 example.duskware.de  ::         16   64    0 0.00000  0.000000 3.99217


>How-To-Repeat:
s/a

>Fix:
Workaround is to use the IPv4 adress in ntp.conf.