[ntp:questions] Can sync via IPv4 but not IPv6?

mayer at gis.net mayer at gis.net
Thu Mar 3 13:46:36 UTC 2005


----- Original Message Follows -----
> I have a number of hosts from which I provide time service to
> customers. These hosts all work perfectly fine via the IPv4 layer.  I
> am seeing behavior on the IPv6 layer that I can't explain...
> 
> The IP addresses and such below are real - I invite anybody to test
> against them, if you think it will be of use.  Obviously, attacks are
> not welcome and will be referred to my security and legal departments.
> 
> 
> Some pertinent information about the server host shown below...
> 
> SunOS 5.8 (Solaris 8) Generic_108528-18
> Sun UltraSPARC Netra (SUNW,UltraSPARC-IIi-cEngine)
> Running NTP daemon version 4.2.0 (release)
> 
> 
> Here's the error I get from the client.
> 
> # bin/ntpdate -6 2001:418:0:7000::53
> Looking for host 2001:418:0:7000::53 and service ntp
> host found : resolv1.nycmny01.us.to.verio.net
> 26 Feb 00:34:44 ntpdate[8801]: no server suitable for synchronization
> found
> 
> 
> Looking on the server, I see that ntpd is bound to the IPv6
> interfaces. This output is from lsof; I have wrapped some of the
> lines.
> 
> ntpd 27693 root 5u  IPv6 0x300043d75c0 0t0 UDP *:ntp (Idle)
> ntpd 27693 root 9u  IPv6 0x300016811d0 0t0 UDP localhost:ntp (Idle)
> ntpd 27693 root 10u IPv6 0x300015abd00 0t0
>                     UDP [fe80::a00:20ff:fed9:d5a8]:ntp (Idle)
> ntpd 27693 root 11u IPv6 0x300011db708 0t0 UDP [2001:418:3ff::53]:ntp
> (Idle) ntpd 27693 root 12u IPv6 0x300049681d0 0t0
>                     UDP resolv1.nycmny01.us.to.verio.net:ntp (Idle)
> 
> 
> This is a snoop of the session traffic.  It looks like exactly what I
> would expect, making things even more confusing.
> 
> ..:fe9e:bfa0 is a randomly chosen client host.
> 
> 2001:418:3ff:2:a00:20ff:fe9e:bfa0 -> 2001:418:0:7000::53
>     NTP  client (Sat Feb 26 00:41:26 2005)
> 2001:418:0:7000::53 -> 2001:418:3ff:2:a00:20ff:fe9e:bfa0
>     NTP  server (Sat Feb 26 00:41:26 2005)
> 2001:418:3ff:2:a00:20ff:fe9e:bfa0 -> 2001:418:0:7000::53
>     NTP  client (Sat Feb 26 00:41:27 2005)
> 2001:418:0:7000::53 -> 2001:418:3ff:2:a00:20ff:fe9e:bfa0
>     NTP  server (Sat Feb 26 00:41:27 2005)
> 2001:418:3ff:2:a00:20ff:fe9e:bfa0 -> 2001:418:0:7000::53
>     NTP  client (Sat Feb 26 00:41:28 2005)
> 2001:418:0:7000::53 -> 2001:418:3ff:2:a00:20ff:fe9e:bfa0
>     NTP  server (Sat Feb 26 00:41:28 2005)
> 2001:418:3ff:2:a00:20ff:fe9e:bfa0 -> 2001:418:0:7000::53
>     NTP  client (Sat Feb 26 00:41:29 2005)
> 2001:418:0:7000::53 -> 2001:418:3ff:2:a00:20ff:fe9e:bfa0
>     NTP  server (Sat Feb 26 00:41:29 2005)
> 
> 
> Thanks in advance for any help!  I am at a loss at this point...
> 
>  -dan

I'd try a different server. That system is apparently not responding to
queries. I noticed that although there is a PTR record for this host
there is no AAAA record in the DNS. I'm not sure why it needs to find
the reverse address.

Danny



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