Network Time Protocol - Wikipedia
Android OS - strange UDP traffic on port 123 - Android Enthusiasts Stack Exchange
LayerStack Tutorials - LayerStack - How to check if TCP / UDP port is open on Linux & Windows Cloud Servers
Fast Troubleshooting for Windows Time Service (w32time) Synchronization
NTP best practices - KB & Manual - ADAMnetworks
Troubleshooting TCP and UDP Port Status
Port numbers, URLs, and IP addresses | Deep Security
Still blocking ntp ports for outbound 123? | AT&T Community Forums
InfoSec Handlers Diary Blog - SANS Internet Storm Center
Network Time Protocol (NTP) (Building Internet Firewalls, 2nd Edition)
SG500 - NTP IP-Helper - Cisco Community
memcached on port 11211 UDP & TCP being exploited - SENKI
How to unblock UDP port 123 and NTP time sync | SmallNetBuilder Forums
Help to configure Traffic Policy for NTP in NE40E
InfoSec Handlers Diary Blog - SANS Internet Storm Center
RHEL: firewall-cmd
Understanding and mitigating NTP-based DDoS attacks
Preventing NTP Reflection Attacks | Acunetix
Top 100 Common Ports (TCP & UDP) - NetworkVerge
Netmetr udp 123 and 5060 ports errors - SW tweaks - Turris forum
LayerStack Tutorials - LayerStack - How to check if TCP / UDP port is open on Linux & Windows Cloud Servers
Windows Firewall
What is port 123?
