Ubuntu - UDP Traffic on port 123 - Unix & Linux Stack Exchange
How to configure a firewall for Active Directory domains Apr 28, 2020 Ubuntu - UDP Traffic on port 123 - Unix & Linux Stack Exchange UDP port 123 is the default NTP port. So check your NTP configuration. The most probably it's standard synchronization. You'd have to capture packets with tcpdump and inspect the content (wireshark).
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Inbound UDP port 123 (NTP) blocked/filtered by AT&T | AT&T
UDP Port Scanner, Online UDP Port Scan, UDP Port Scanning UDP Port Scanner. With this online UDP port scanner you can scan an IP address for open UDP ports. Use this UDP port scan tool to check what services (dns, tftp, ntp, snmp, mdns, upnp) are running on your server, test if your firewall is working correctly, view open UDP ports. Inbound UDP port 123 (NTP) blocked/filtered by AT&T | AT&T May 08, 2019 How to disable inbound UDP for Azure services Apr 23, 2020