How to Configure Time Server (NTP Server) on Centos 7?


VM/ Physical – It is recommended to have the time server as a physical server, but VMs should be okay depending on your setup and requirement. My virtual lab environment is VMware based so here’s the guide for a VM. Once the CentOS Minimal is installed on the VM make sure to install open-vm-tools.

If you are not conformable with Vi Editor please use install nano for editing.

Installing the time server:

  1. First we need to install NTPd . to do this open command line :

  2. Then open NTP main configuration file for editing:
    If you are planning on hosting your time servers externally like time01.yourdomain.com, time02.yourdomain.com with ports 123 open on the firewall. Each of the time server will be talking to 0.us.pool.ntp.org, 0.us.pool.ntp.org, 0.us.pool.ntp.org, 0.us.pool.ntp.org. Later on you can probably add your time servers to the NTP.org by joining the pool. For my example, I am not using the centos default pool, but i am using the U.S. zone. For internal servers/workstations you can point it to the local ip/dns name for the local time servers.

  3. Then start and enable ntp server:

  4. You need to allow ntp service on firewall(NTP service uses UDP port 123). So run next command:

  5. Verify you ntp service with next command:

Your output should be similar to:

Delete Files and Folders Older Than X Days

Often times admin have to creates tasks like removing log files or some other files on a regular schedule. Here is an automated way of removing files / folders older than X days.

Create a Batch file or Powershell script and add it to scheduled task.

Please check permissions on the files and folders. If you have unique or specialized permission on the file or folders these wont work.

Batch File:



How to Start and Enable Firewalld on CentOS 7

It is highly recommended that you have a firewall protecting your server.

Pre-Flight Check

  • These instructions are intended specifically for enabling and starting firewalld CentOS 7.
  • I’ll be working from a Liquid Web Self Managed CentOS 7 server, and I’ll be logged in as root.

Check the Status of Firewalld

To check the status of firewalld, run the following command as root:

Enable Firewalld

To enable firewalld, run the following command as root:

Start Firewalld

To start firewalld, run the following command as root: