Setting up Fail2Ban for avoiding different kinds of Brute Force Attacks

OBJECTIVE

To prevent the server from bruteforce attacks. Fail2ban will monitor the service and block the persons try to harm our server.

How to setup Amazon EC2 API on Linux Machine

OBJECTIVE

The objective of this how to is to enable the use of various command line tools of Amazon such as EC2 API, S3 API, Route53 API, etc.

Setup DKIM keys with Sendmail

OBJECTIVE

The purpose of this document is to enable DKIM keys setup on sendmail server so that email delivery into inboxes can be maximized.

Get Real Visitor IP in Apache Logs running behind a Load Balancer

OBJECTIVE

The objective of this tutorial is to configure Apache webserver log settings to show the real visitor IP when Apache is running behind Load Balancer.

Redirect xyz.com to www.xyz.com

Many times we meet with a situation where we need to redirect root domains to www. With apache htaccess file you can put the following rule in .htaccess file of webroot directory of your domain

Troubleshooting MySQL Master-Slave Replication Errors

Many times I have seen broken MySQL Master-Slave syncing on various servers because of Duplicate Entry Errors. So here I am suggesting steps to overcome these issues.

Export Data to CSV Format in PostgreSQL

OBJECTIVE

The objective of this article is to enable the system administrator to convert postgreSQL data in CSV format

Centralized Management with Puppet on CentOS 5

Introduction

Puppet is a configuration automation tool that allows you to centralize management of the various Linux flavors running on your network. Puppet supports central management of the important aspects of your systems, such as: files, packages, users, services, cron, mounts, etc.

This is a step by step tutorial on how to install the Puppet Server (puppetmaster) on one machine, and the Puppet Client (puppetd) on another. We then perform a simple test to make sure Puppet is working properly.

How to Avoid SYN Cookies DOS Attacks

SYN Flooding is the most common DDOS attack. I have tried to explain some tweaks through which you can avoid these attacks.

Troubleshooting Linux Filesystem Issues

At any moment a system admin may come across file system failures due to issues with data structures (or objects such as inode, directories, superblock etc. This can be caused by any reason:

  • Buggy device driver or utilities (especially third party utilities)
  • Mistakes by System Admin
  • Kernel bugs

Due to Filesystem Failure:

  • File system will refuse to mount
  • Entire system get hangs
  • Even if filesystem mount operation result into success, users may notice strange behavior when mounted such as system reboot, gibberish characters in directory listings etc