UDP port123 blocked

Hi

Wanted to get a server answering NTP requests but using the internal RTC 
as a time reference as discussed in the Chrony docs. Could not get it to 
work.

Scenario: Rocky 8.5 OS on old Intel server with Chrony version 4.1 
(+READLINE +SECHASH +IPV6 +DEBUG). Testing with a Linux Mint laptop.

When testing with ntpdate -q 123 192.168.100.10 gave message:

no server suitable for synchronization found

After digging around with the Chrony conf file and getting nowhere, I 
found in the mailing list some hint to test:

mtr -u -P 123 192.168.100.10

Keys:  Help   Display mode   Restart statistics   Order of fields   quit
Packets               Pings
  Host Loss%   Snt   Last   Avg  Best  Wrst StDev
  1. (no route to host)

Eliminated the usual suspects: Firewall (iptables) on both sides are 
off. I can ping  interfaces from each other.

Chrony reportedly runs:

@localhost ~]$  systemctl status chronyd

● chronyd.service - NTP client/server
    Loaded: loaded (/usr/lib/systemd/system/chronyd.service; enabled; 
vendor pre>
    Active: active (running) since Tue 2022-06-28 10:22:57 EDT; 1h 8min ago
      Docs: man:chronyd(8)
man:chrony.conf(5)
   Process: 1180 ExecStartPost=/usr/libexec/chrony-helper update-daemon 
(code=ex>
   Process: 1103 ExecStart=/usr/sbin/chronyd $OPTIONS (code=exited, 
status=0/SUC>
  Main PID: 1115 (chronyd)
     Tasks: 1 (limit: 46109)
    Memory: 1.6M
    CGroup: /system.slice/chronyd.service
            └─1115 /usr/sbin/chronyd

Jun 28 10:22:52 localhost.localdomain systemd[1]: Starting NTP 
client/server...
Jun 28 10:22:52 localhost.localdomain chronyd[1115]: chronyd version 4.1 
starti>
Jun 28 10:22:52 localhost.localdomain chronyd[1115]: Frequency 11278.843 
+/- 99>
Jun 28 10:22:57 localhost.localdomain systemd[1]: Started NTP client/server.

*So it seems the udp port is blocked or is Chrony is not listening on 
that port?*

Key items in Chrony.conf is:

server 196.10.52.58 offline

manual

makestep 1.0 3

minsources 1

rtcdevice /dev/rtc

local stratum 8

logdir /var/log/chrony

log measurements statistics tracking

Any idea what could be the problem?

Regards

deon