Setup SFTP on UBUNTU 16.x with Active Directory authentication

In this tutorial we will look into setting up sftp server for users on Ubuntu 16 which will be authenticating through Active Directory. This will be a two step process consisting of first connecting Ubuntu server to Active Directory and then setting up SFTP for AD users.

Cpanel whm server sending spam mail

We had a case when one of the customers complained of being blacklisted because his whm server was sending spam. We had to act fast in order to stop this. We did the following.

How to copy files and directories between Linux hosts with scp

In this how to we will go over scp copy command and how it can be used to securely copy files between Linux hosts. SCP uses SSH for data transfer and also uses it for authentication. By default SCP works on port 22 which is default ssh port. For security reasons it is recommended to…

Using TLS Encription with Postfix CentOS 6

This tutorial based on CentOS 6.4 Linux Asymmetric encryption uses key pair public and private. With asymmetric encryption we use digital certificates to discover other people public keys. Certificate stores information like Organization name , users email address , department and so on. Before encrypted communication starts one of the party’s sends public certificate to…

Protect CentOS Linux system with SELinux

In many cases users simply turn off SELinux due to lack of understanding of this great security feature provided with every RedHat , CentOS , Fedora and some other Linux distributions. Another popular alternative, available on Novell’s SuSE Linux and Canonical’s Ubuntu platform, is called AppArmor. In this article we will take closer look at…

Secure Router with IP access control lists (ACLs)

In this article we will look at very basic security feature of routers and L3 switches – Access Lists At the most basic level, an access list is a list of conditions that categorize packets and because of this, they can be really helpful when you need to exercise control over network traffic. One of…

Install Nagios NRPE from source code on CentOS or Debian

In order to monitor internal resources of remote systems with Nagios you will need NRPE installed and configured on a client. There will be two pieces to install NRPE daemon and nrpe plugins. This particular install was tested with CentOS and Debian.