Tag: Ubuntu Server

NTP Client Setup – Ubuntu 22.04

Blake

The following tutorial will cover how to enable the NTP client on Ubuntu. When working with Linux servers, the system time must be accurate. The best way to do that is by using the Network Time Protocol.

The first step is to install the NTP client.

sudo apt install ntp

Before we begin configuration, let’s back up the default NTP client config. We will use today’s date in the command.

sudo cp --archive /etc/ntp.conf /etc/ntp.conf-COPY-$(date +"%Y%m%d%H%M%S")

Open the config file using your favourite text editor. In my case, I will be using nano.

sudo nano /etc/ntp.conf

The first thing we want to do is comment out the current servers that ships with Ubuntu. Add a # in front of all the “pool” lines.

Head to NTP Pool and find the closest pool address to your machine. In my case, I am in Canada, so I’m going to add the following to the bottom of my ntp.conf file.

You can do this all in one command if you would like.

sudo sed -i -r -e "s/^((server|pool).*)/# \1         # commented by $(whoami) on $(date +"%Y-%m-%d @ %H:%M:%S")/" /etc/ntp.conf
echo -e "\npool ca.pool.ntp.org iburst         # added by $(whoami) on $(date +"%Y-%m-%d @ %H:%M:%S")" | sudo tee -a /etc/ntp.conf

We will restart the NTP client service once you have saved and closed the config file.

sudo service ntp restart

Let’s check to see if the service is running.

sudo ntpq -p

The following output should show.

Output of the ntpq command. This is showing the list of server NTP is getting time from.

That’s it! Your box will always get its time from the ntp pool; no more out-of-sync log files.

This tutorial was found in the How-To-Secure-A-Linux-Server GitHub repository. If you have any questions, please drop a comment below.

Apache2 Server Signature

Blake

The following tutorial will provide you with the steps required to disable server information on folder list pages and any of the error pages. The following screenshot shows what I am talking about.

Server Info

I will be showing how I did this on Ubuntu Server 14.04.4 LTS.

This information can provide a hacker with the versions of software installed on your server. Depending on your configuration, PHP information is shared as well. Lets go ahead and get this secured.

First we want to open the apache2.conf in our favorite text editor.

sudo nano /etc/apache2/apache2.conf

Next, we will add a few lines to the end of the config.

ServerSignature Off
ServerTokens Prod

We will now want to restart Apache.

sudo service apache2 restart

On a folder page or error code page you will see the version information is now gone. Unfortunately PHP still sends version information in the page header. To turn that off we need to edit one more config.

sudo nano /etc/php5/apache2/php.ini

Change the expose_php from “On” to “Off”. You will need to find the line in the php.ini file.

expose_php = Off

We can now save the file and restart Apache.

sudo service apache2 restart

We are done! Version numbers will no longer be view-able.
If you have any questions, please use the comments bellow!