> On Oct 18, 2015, at 08:03, Marcin Wisnicki <mwisnicki+freebsd at
gmail.com> wrote:
>
> My ntpd stopped synchronizing clock sometime ago (default ntp.conf).
>
> To debug the problem I've tried running ntpdate and got strange
results:
>
>> # ntpdate 0.freebsd.pool.ntp.org
>> 18 Oct 13:53:14 ntpdate[55102]: no server suitable for synchronization
found
>>
>> # ntpdate -u 0.freebsd.pool.ntp.org
>> 18 Oct 13:53:19 ntpdate[55119]: adjust time server 193.25.222.240
offset 0.002672 sec
>
>
> This would point to broken firewall BUT:
>
>> # nmap -p123 -sU 0.freebsd.pool.ntp.org
>>
>> Starting Nmap 6.49BETA5 ( https://nmap.org ) at 2015-10-18 13:52 CEST
>> Nmap scan report for 0.freebsd.pool.ntp.org (193.25.222.240)
>> Host is up (0.027s latency).
>> Other addresses for 0.freebsd.pool.ntp.org (not scanned): 94.154.96.7
95.158.95.123 46.175.224.7
>> rDNS record for 193.25.222.240: afrodyta.complex.net.pl
>> PORT STATE SERVICE
>> 123/udp open ntp
>>
>> Nmap done: 1 IP address (1 host up) scanned in 0.64 seconds
>
> So there is nothing blocking the traffic.
>
> Any ideas ?
Both ?nmap" and ?ntpdate -u? would use an unprivileged, ephemeral port,
while ntpd(8) and a regular run of ntpdate(8) would use UDP 123 as the source
port. Perhaps there is a firewall issue with source ports lower than 1024?