Deploing CentOS 7 with postfix, MailScanner, spamassassin, ClamAV as SMTP gateway

In this blog we will look into building smtp scanner gateway based on Postfix, Mailscanner , spamassassin and clamav. In this example we have CenOS 7 minimal deployed on the internal network. Perimeter firewall is setup with NAT translating public IP port 25 to internal mailscanner gateway 192.168.0.5. Internal Mail server itself can run any…

How to setup Master Slave DNS with Bind and CentOS 6.x

In this how to we will look into setting up two name DNS servers master and slave using Bind and CentOS 6.5. We will setup primary zone labzone.local on dns1.local server and slave zone labzone.local on dns2.local server. We assume our DNS information is public and will not setup chrooted environment although for additional security…

Building CentOS 7 NetFlows Monitoring station with nfsen and nfdump

In this article we will look into setting up NetFlows monitoring station with open source tools. It is extremely important to keep track of what is happening on your network, who are the highest talkers and which users or programs accessing which resources. In our LAB example we will have Cisco Router on which we…

Add second swap partition on CentOS 6

Swap space is extremely important for Linux system. It acts like temporary storage for process memory image. There are many reasons to have multiple swap areas. We will take a look at the process of creating additional swap partition on already existing system. In our example system was partiiotned with 3 primary partitions. / /boot…

How to setup TigerVNC on CentOS 6

VNC While alternatives are available, the simplest way to configure remote access to CentOS Linux is via VNC. In our example we will use TigervVnc. TigerVNC is feature rich and has built-in encryption support. Alternatively you could use TurboVNC , TightVNC and so on.

Building simple DRBD Cluster on Linux – CentOS 6.5

The Distributed Replicated Block Device (DRBD) is a Linux Kernel module that constitutes a distributed storage system. In this blog we will look into setting up very simple replication cluster between 2 partition /dev/sdb1 located on 2 nodes u1.local and u2.local. You can use DRBD to share block devices between Linux servers to share file…

Virtual machine running multiple wordperss installations

This is how we would setup virtual machine running multiple wordperss installations. In some cases we want to create dedicated vm for running strictly wordpress. This is not a secure deployment and better suited for development environment. For production installation would have to be hardened and some sort of HIDS should be in place.

Deploy samba RedHat or CentOS 7

By definition samba is network file and print sharing service that is supported by most operating systems today. In this blog we will take a look at deploying samba server on REDHAT 7 system to share files with Windows 7 or 8 based client. The procedure will be same on CentOS, and most other distributions…

How to configure Interface Teaming with LACP using CentOS 7 and Redhat 7

Interface teaming is introduced in RHEL7 as an additional choice to implement fault tolerance and enhance throughput. It is widely considered more superior technique then Nic bonding and has much superior handling of packet flow then bonding. In this blog we will configure Nic teaming with LACP

Scripting libvirt with php on CentOS or Redhat 7

Libvirt is virtualization API used to interact with different hypervisorrs. In this article we will look into scripting with php using libvirt api. This is very basic overview and designed for very basic scripting needs. This particular configuration was tested against KVM on CentOS 7. In order to script libvirt with php we will need…