February 1, 2015 / / HowTo Guide

GNS3 team has done a great job in stabilizing the ASA implementation.

On the new version1.2.1 they have already set all default options (kernel command and Qemu options) to the best possible set that is out there( which you see below).

And they have also stabilized the cpu utilization issue with ASA by integrating cpulimit and given you an option to choose for the Qemu process priority and cpu % allocation.

So you’ve got most of your work cut out.

Read the Post ASA Install GNS3

January 27, 2015 / / HowTo Guide

This guide explains how to configure PXE server in Ubuntu 14.10 PXE Server, stands for preboot execution environment, is used to enable a network computer to boot only from a network interface card. This method will be very helpful, if a System Administrator wants to install many systems which doesn’t have a CD/DVD device on the network. PXE environment needs a DHCP server that distributes the IP addresses to the client systems, and a TFTP server that downloads the installation files to the PXE clients. You don’t need any CD/DVD or USB bootable drives to install client systems. Just, copy the ISO images on the PXE server and start installing your Linux clients via network using PXE server.

Read the Post Ubuntu 14.10 PXE server installation

January 27, 2015 / / Linux Tips

I recently treated myself to a long overdue syslog server for our network devices. The system is on a Linux system (I would have it no other way) and has been instrumental to troubleshooting and auditing these past few weeks. You can read this article for some log parsing tricks ranging from basic to a bit more advanced.

Read the Post Tail Cat and Grep Your Log Files

January 12, 2015 / / HowTo Guide
Security Onion is a Linux distro for intrusion detection, network security monitoring, and log management. It’s based on Ubuntu and contains Snort, Suricata, Bro, OSSEC, Sguil, Squert, Snorby, ELSA, Xplico, NetworkMiner, and many other security tools. The easy-to-use Setup wizard allows you to build an army of distributed sensors for your enterprise in minutes!

Read the Post Evaluate Security Onion on Ubuntu 12.04

November 19, 2014 / / HowTo Guide
  • Generate a single alert when something goes wrong. Don’t spam.
  • Be able to alert on both volume of a particular message or lack thereof
  • If alerting on lack thereof, alert even if there was 0 messages during the period

I started with the throttle filter but felt the use case I wanted to use was a bit different than that filter was intended to do. I used it’s code as a base for this filter. Disclaimer: This is my first attempt at Ruby, so I am sure it is quite rough code wise.

Read the Post Adding Alert to Logstash

November 19, 2014 / / Linux Tips
November 19, 2014 / / HowTo Guide

I was recently asked if it was possible to forward vCenter Server logs to a regular syslog server and if so, how difficult would it be to setup? I had researched this topic several years back, but did not find an ideal solution as vCenter Server was only available on the Windows platform and vCenter Server itself did not provide any syslogging capabilities. With the release of vSphere 5.0, VMware introduced the VCSA (vCenter Server Appliance) and realized I never revisited this question for the VCSA.
Read the Post vCenter Syslog setup

November 17, 2014 / / Linux Tips

Most of web-based application development todays were developed using database. The most popular one is using PHP and MySQL. When developing using MySQL most of beginners were using phpMyAdmin as their power tools in database CRUD (Create-Read-Update-Delete) as well as databases/tables creation and manipulation.

PhpMyAdmin supports encryption feature which enables database developers to raise their application security bar in database. In order to use encryption feature in PHP, phpMyAdmin need a PHP library called mcrypt to be enabled. If it is not already installed during php installation, then you have to enabled it on php.ini either manually or automagically

Read the Post Easy Install PHP Mcrypt Extension on Ubuntu Linux

November 17, 2014 / / HowTo Guide

If you have shell or telnet access to your web server, you can backup your MySQL data by using the mysqldump command. This command connects to the MySQL server and creates an SQL dump file. The dump file contains the SQL statements necessary to re-create the database. Here is the proper syntax:

$ mysqldump –opt -u [uname] -p[pass] [dbname] > [backupfile.sql]
  • [uname] Your database username
  • [pass] The password for your database (note there is no space between -p and the password)
  • [dbname] The name of your database
  • [backupfile.sql] The filename for your database backup
  • [–opt] The mysqldump option

Read the Post Backing up mysql using mysqldump

November 17, 2014 / / Linux Tips

How do I create a custom static HTTP 404 or HTTP 403 error page under nginx web server?

First create 404.html in your document root. The default is location is /usr/local/nginx/html/. So create a HTML file as follows:

Read the Post NGINX create custom 404 page

November 16, 2014 / / HowTo Guide
November 16, 2014 / / Linux Tips
October 27, 2014 / / Learning Linux

In this document we describe an installation of Puppet configuration manager on a Ubuntu Linux 14.04 Trusty Tahr. The installation will be followed by a simple puppet manifest example to make sure that installation was successful and puppet ready to use as standalone deployment.

Read the Post Puppet installation on Linux Ubuntu 14.04 Trusty Tahr

October 27, 2014 / / Linux Tips


As a lot of articles and programs require to have Java installed, this article will guide you through the process of installing and managing different versions of Java.

Installing default JRE/JDK

This is the recommended and easiest option. This will install OpenJDK 6 on Ubuntu 12.04 and earlier and on 12.10+ it will install OpenJDK 7.
Read the Post How To Install Java on Ubuntu with Apt-Get

October 27, 2014 / / HowTo Guide

UFW – Uncomplicated Firewall

The default firewall configuration tool for Ubuntu is ufw. Developed to easeiptables firewall configuration, ufw provides a user friendly way to create an IPv4 or IPv6 host-based firewall. By default UFW is disabled.

Read the Post Ubuntu using UFW firewall

October 9, 2014 / / Linux Tips
       grc will execute command command with optional parameters [args] piping
       its stdout or stderr into grcat, with apropriate configuration file.

       Configuration file for grc is determined by /etc/grc.conf file.

       Format of /etc/grc.conf:  each  entry  consists  of  2  lines,  between
       entries  there can be any number of empty lines or lines beginning with
       # (comments)
 Read the Post Tailing Log files in Colour
September 23, 2014 / / Linux Tips
September 19, 2014 / / HowTo Guide

There are two ways to create an SSH tunnel, local and remote port forwarding (there’s also dynamic forwarding, but we won’t cover that here). The best way to understand these is by an example, let’s start with local port forwarding.

Imagine you’re on a private network which doesn’t allow connections to a specific server. Let’s say you’re at work and domain.com is being blocked. To get around this we can create a tunnel through a server which isn’t on our network and thus can access domain.com
Read the Post SSH Tunnel and Port Forwarding

September 19, 2014 / / Linux Tips
September 19, 2014 / / Linux Tips
September 19, 2014 / / Linux Tips
September 19, 2014 / / HowTo Guide
September 19, 2014 / / Linux Tips
September 19, 2014 / / HowTo Guide

This guide will help you easily set up a email server On Ubuntu using Qmail as MTA, OpenLDAP as a back-end for users, and Courier IMAP for IMAP server.

Qmail is a secure, reliable, efficient, simple message transfer agent. It is designed for typical Internet-connected UNIX hosts. As of October 2001, qmail is the second most common SMTP server on the Internet, and has by far the fastest growth of any SMTP server.
Read the Post Qmail OpenLdap On Ubuntu

September 19, 2014 / / HowTo Guide

 Looking to monitor my SSH server and trigger an email alert for any SSH connections to my Ubuntu server I’ve pulled together a very basic script that will send an email when someone logs into an SSH server. Read on…

My ssh server is based around Openssh. Openssh executes the file /etc/ssh/sshrc if it exists when a user logs in via SSH. By default I did not have an sshrc file so I created one as follows to enable an email script to be executed on connection.
Read the Post Setup Ubuntu or Debian for ssh connection Alerts

September 19, 2014 / / HowTo Guide

This tutorial shows how to set up a USB-over-IP server with Ubuntu 10.04 as well as a USB-over-IP client (also running Ubuntu 10.04). The USB/IP Project aims to develop a general USB device sharing system over IP network. To share USB devices between computers with their full functionality, USB/IP encapsulates “USB I/O messages” into TCP/IP payloads and transmits them between computers. USB-over-IP can be useful for virtual machines, for example, that don’t have access to the host system’s hardware – USB-over-IP allows virtual machines to use remote USB devices.
Read the Post Share USB ThumbDrives Across your Network

September 19, 2014 / / HowTo Guide

tmux and GNU Screen are well-known utilities which allow multiplexing of virtual consoles. Using either, it is possible to start a session, detach, move to a different machine and resume the session in uninterrupted progress. It’s also possible to use these tools to share a single session between more than one user at the same time.
Read the Post Terminal Sessions With Tmux And Screen

September 19, 2014 / / HowTo Guide

Cassandra is a distributed database with a BigTable data model running on a Dynamo like infrastructure. It is column-oriented and allows for the storage of relatively structured data. It has a fully decentralized model; every node is identical and there is no single point of failure. It’s also

extremely fault tolerant; data is replicated to multiple nodes and across data centers. Cassandra is also very elastic; read and write throughput increase linearly as new machines are added.
Read the Post Cassandra on Ubuntu

September 19, 2014 / / HowTo Guide

This tutorial describes how to set up database replication in MySQL using an SSL connection for encryption (to make it impossible for hackers to sniff out passwords and data transferred between the master and slave). MySQL replication allows you to have an exact copy of a database from a master server on another server (slave), and all updates to the database on the master server are immediately replicated to the database on the slave server so that both databases are in sync. This is not a backup policy because an accidentally issued DELETE command will also be carried out on the slave; but replication can help protect against hardware failures though.

Read the Post Set Up MySQL Database Replication With SSL Encryption

September 19, 2014 / / HowTo Guide

Dstat is a versatile replacement for vmstat, iostat, netstat and ifstat. Dstat overcomes some of their limitations and adds some extra features, more counters and flexibility. Dstat is handy for monitoring systems during performance tuning tests, benchmarks or troubleshooting.

Dstat allows you to view all of your system resources in real-time, you can eg. compare disk utilization in combination with interrupts from your IDE controller, or compare the network bandwidth numbers directly with the disk throughput (in the same interval).
Read the Post Monitoring Linux with Dstat