[Pool] Monitoring says my server is unreachable

Marek Podmaka marki at marki-online.net
Wed Feb 26 18:45:19 UTC 2014

Hello Steven,

Thanks, that seems like a very good hint.

However I am receiving some packets also from clients with src port !=
123, so it must be "someone" in between who is doing the filtering
(and not my direct provider).

Ask, maybe you can check the database if any other servers became
unreachable this morning (last reply from my server on the monitoring
website is from today 04:02, I guess UTC).

Wednesday, February 26, 2014, 17:02:19, you wrote:

> From my US-based client"

> ntp requests with UDP src port == 123 work.
> ntp requests with UDP src port != 123 are blocked (perhaps in Europe).

> I suspect that the pool monitoring uses UDP src!= 123.   

> On Wed, Feb 26, 2014 at 6:15 AM, Marek Podmaka <marki at marki-online.net> wrote:
> Hello,
>  Today I have received report from pool that it cannot connect to my
>  IPv4 server (IPv6 on the same server works OK). I guess monitoring is
>  in USA.
>  Also website http://keetweej.vanheusden.com/query_ntp.php says it
>  cannot connect. That appears to be in Netherlands.
>  My server ( is working OK, queries from clients are
>  coming (about 20 packets/s currently) and NTP answering on them. I
>  have tested from my other server in Germany and from there it works. I
>  have also confirmed that entire subnet seems to be blocked from those
>  servers/countries. My direct connectivity provider says they don't
>  block it on their side.
>  Any ideas how to troubleshoot further? Can you test from other
>  coutries and report if can't get time from me? (monlist is blocked,
>  but for example ntpdate -q should work). So it seems
>  like it is blocked somewhere in the transit.
>  --
>    bYE, Marki
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  bYE, Marki

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