Once you configure NTPD service on your RHEL7 linux you will need to allow traffic through the firewall on port 123. Te following linux command will enable all public traffic on UDP port 123:
# firewall-cmd --zone=public --add-port=123/udp --permanent
success
To apply the above changes reload your firewall:
# firewall-cmd --reload
success
Use iptables-save command to confirm that UDP port 123 is now accessible:
# iptables-save | grep 123
-A IN_public_allow -p udp -m udp --dport 123 -m conntrack --ctstate NEW -j ACCEPT
enable port 123 UDP ntp rhel7 linux

Alternatively you can use graphical tool firewall-config to allow NTP port 123 on your Linux system.
ARE YOU LOOKING FOR A LINUX JOB?
Submit your RESUME, create a JOB ALERT or subscribe to RSS feed on LinuxCareers.com.
LINUX CAREER NEWSLETTER
Subscribe to NEWSLETTER and receive latest news, jobs, career advice and tutorials.
DO YOU NEED ADDITIONAL HELP?
Get extra help by visiting our LINUX FORUM or simply use comments below.

You may also be interested in: