If you are connecting remotely to a server via SSH for this tutorial then there is a very real possibility that you could lock yourself out of your machine. iptables -F We used the -F switch to flush all existing rules so we start with a clean state from which to add new rules.

iptables to redirect NTP traffic question (self.networking) submitted 4 years ago * by iluomo. Our Server makes an NTP query to 123.123.123.123. Iptables rules needs to forward that request to [OUR PUBLIC IP], and return the packet(s) to the server such that it appears the return packet(s iptables -A OUTPUT -o eth0 -p udp -s --sport 123 -d --dport 123 -m state --state NEW -j ACCEPT. the -m state is for stateful filtering; you could just as well leave it off and use -j ACCEPT to blanket accept traffic for this rule. This tutorial will help you install and configure NTP server using Chrony on RHEL 8. NTP (Network Time Protocol) is a network protocol that allows for clock synchronization between computer systems. Chrony is a versatile implementation of the Network Time Protocol. The NTP (Network Time Protocol RFC-1305) Also note that this tutorial should work for all modern Red Hat based systems including Fedora and CentOS. Below is an example iptables rule that allows NTP traffic from ANY source. This is just an example and should be checked against your How to set up NTP server in CentOS. Last updated on April 27, and let employees use the internal server as opposed to public NTP servers. In this tutorial, we will describe how to configure a CentOS system as an NTP server. # iptables -A INPUT -s 192.168.1./24 -p udp --dport 123 -j ACCEPT NTP stands for Network Time Protocol. It is used to synchronize the time on your Linux system with a centralized NTP server. A local NTP server on the network can be synchronized with an external timing source to keep all the servers in your organization in-sync with an accurate