Contact for queries :


  UpComing Live WebEx Workshop Series

Securing NTP with iptables

Like the DHCP server, NTP requires only firewall rules to operate (no SELinux configuration is necessary).
The NTP service uses TCP and UDP port 123, so you need to open both on the firewall.
Step 1. Use iptables to create the required firewall rules:

# iptables -I INPUT 5 -p udp -m udp –dport 123 -j ACCEPT
# iptables -I INPUT 5 -p tcp -m tcp –dport 123 -j ACCEPT

Step 2. Save the firewall rules you just created:

# service iptables save
Saving firewall rules to /etc/sysconfig/iptables: [ OK ]

Step 3. Then restart the iptables service:

# service iptables restart
iptables: Flushing firewall rules: [ OK ]
iptables: Setting chains to policy ACCEPT: filter [ OK ]
iptables: Unloading modules: [ OK ]
iptables: Applying firewall rules: [ OK ]

November 16, 2015

1 responses on "Securing NTP with iptables"

Leave a Message

Your email address will not be published. Required fields are marked *


IGURKUL I.T. Training Hub offering various Career Certification courses in Computer Networking, Unix, Linux, Cloud Computing and DevOps Technologies. With its rich experience in IT training service sector, iGURKUL has been able to set Industry best practices in IT Training for the past five years.

In Past five years, more than 5000 professionals have been trained by iGURKUL for System administration, Cloud Computing and DevOps Skill set through our Online Training portal And , each day , more than 10000 working professionals from all over the globe visiting our knowledge base for the best practices and Knowledge learning.

copyright protected - 2011 © igurkul I.T. solutions. All rights reserved.