Category Archives: Linux Tips & Tutorials
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
How to install memcache
In the beginning we need to install libevent because of memcached dependency
Check if libevent is installed or not?
MySQL Master-Slave Configuration
In this tutorial, I have only shown the commands to configure Master-Slave replication as the details, pros/cons of the setup is available throughout the web.