[pkg-ntp-maintainers] Bug#670657: large offsett with ipv6 enabled

[Estelmann, Christian]

Package: ntp
Version: 1:4.2.6.p2+dfsg-1+b1

Hi,

when IPv6 is enabled (dual stack) and ntpd uses IPv4-only NTP servers the offset is very large. Curiously ntpq shows this.

example:
root@<host with IPv6>:~# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 <source1>        131.188.3.221    2 u   20   64  377    0.246  -11518. 1424.63
+<source2>        131.188.3.221    2 u   18   64  377    0.262  -9841.4 2045.84
 <source3>        131.188.3.220    2 u   26   64  377    0.300  -9220.8 2519.30

After disabling IPv6 (adding "ipv6.disable=1" to GRUB_CMDLINE_LINUX_DEFAULT in /etc/default/grup, running update-grub2 and restarting the machine) everything works fine.

root@<host with IPv6>:~# ntpq -p
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 <source1>         131.188.3.220    2 u   20  128  377    0.263   -1.236   0.622
*<source2>         131.188.3.222    2 u   32  128  377    0.279   -1.334   0.587
-<source3>         131.188.3.221    2 u   16  128  377    0.275   -2.418   0.831


root@<host>:~# cat /etc/debian_version 
6.0.4
root@<host>:~# uname -a
Linux vision07 2.6.32-5-amd64 #1 SMP Thu Mar 22 17:26:33 UTC 2012 x86_64 GNU/Linux

Greetings,
Christian Estelmann