networking - How to check if port 123 is ready for time
NTP Server Online Tester This tool is useful to check if a given Network Time Protocol server is reachable over the internet using IPv4 and IPv6 connectivity. It is also useful for knowing the resulting offset using the exact time of 1a.ncomputers.org stratum 2 NTP public server. It uses ntpdate-q to perform a time synchronization query which works for linux servers, windows servers, etc. 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. How to allow timesync over UDP port 123 (SNTP) and TCP Sep 14, 2009 Open UDP Port 123 Windows Vista Firewall
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Guaranteed communication over port 123 is the key difference between TCP and UDP. UDP port 123 would not have guaranteed communication in the same way as TCP. Because protocol TCP port 123 was flagged as a virus (colored red) does not mean that a virus is using port 123, but that a Trojan or Virus has used this port in the past to communicate. networking - How to check if port 123 is ready for time