networking - How to check if port 123 is ready for time

TIME can operate over either TCP or UDP. When operating over TCP, a host connects to a server that supports the TIME protocol on TCP port 37. The server then sends the time as a 32-bit unsigned binary number in network byte order representing a number of seconds since 00:00 (midnight) 1 January, 1900 GMT and closes the connection. iptables - ubuntu: open udp port 123 - Server Fault into my linux server (Ubuntu 8) I have top open the port 123 for ntp. I have write this into /etc/iptables.rules::INPUT ACCEPT [7496:9080183] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [4393:322232] [0:0] -A INPUT -p udp -m udp --sport 8100 -j ACCEPT [0:0] -A INPUT -p udp -m udp --dport 8100 -j ACCEPT [0:0] -I INPUT -p udp --dport 123 -j ACCEPT [0:0] -I OUTPUT -p udp --sport 123 -j … Solved: Opening ports UDP 500, 4500 and 123 - HughesNet

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UDP Port 123 may use a defined protocol to communicate depending on the application. A protocol is a set of formalized rules that explains how data is communicated over a network. Think of it as the language spoken between computers to help them communicate more efficiently.

123 : udp: NTP: Network Time Protocol (NTP) - used for time synchronization Security Concerns: It provides both information and possible avenue of attack for intruders. Info gathered can include system uptime, time since reset, time server pkt, I/O & memory statistics and ntp peer list. If a host is susceptible to time altering via ntp an UDP 123 - Port Protocol Information and Warning! UDP Port 123 may use a defined protocol to communicate depending on the application. A protocol is a set of formalized rules that explains how data is communicated over a network. Think of it as the language spoken between computers to help them communicate more efficiently. TCP/UDP Ports -> Port 123 Port 123. Ports those registered with IANA are shown as official ports. The same port number may be unofficialy used by various services or applications. The official usage are listed separately below its usage may change from time to time. Official