Mohan Cheema

Amazon VPC with OpenSwan and Cisco ASA Site-to-Site VPN

Mohan Cheema — Tue, 10 Apr 2012 12:11:02 +0000

Overview Recently my company want to achieve PCI compliance on Amazon. As per PCI compliance standard Database instance should listen on private IP and should not be accessible from outside world using public IP. This is not achievable using EC2 … Continue reading →

Change / Update SSL certificate for Amazon Elastic Load Balancer

Mohan Cheema — Wed, 30 Nov 2011 03:20:50 +0000

This is in continuation to Amazon ELB SSL Termination HowTo. Earlier we have seen how to setup Elastic Load Balancer with SSL termination on Amazon. Now we will see how do we change the SSL certification once we renew it … Continue reading →

Disable Trace/Track in Apache HTTPD

Mohan Cheema — Fri, 30 Sep 2011 03:43:27 +0000

Introduction Disabling TRACE and TRACK in Apache for PCI-related vulnerabilities like Web Server HTTP Trace/Track Method Support Cross-Site Tracing Vulnerability is surprisingly easy with the Apache web server. The main thing to keep in mind is understanding that if you … Continue reading →

MySQL MultiMaster Replication

Mohan Cheema — Wed, 28 Sep 2011 07:24:37 +0000

You may know about the MySQL Cluster, which is a complex architecture to achieve high availability and performance. One of the advantages of MySQL Cluster is that each node is a peer to the others, whereas in a normal replicating … Continue reading →

How to test Postfix SMTP using Telnet

Mohan Cheema — Thu, 22 Sep 2011 15:12:45 +0000

1. Telnet to postfix mail server using TCP port 25. Command is telnet <servername/serverip> 25 response should be as follows 220 ******************************************** 2. Turn on local echo on your telnet client so that you can see what you are typing. … Continue reading →

Linux Screen Shortcuts

Mohan Cheema — Thu, 18 Aug 2011 08:48:48 +0000

Screen is a much under utilised program, which provides the following functionality: Remote terminal session management (detaching or sharing terminal sessions) unlimited windows (unlike the hard-coded number of Linux virtual consoles) Scroll back buffer (not limited to video memory like … Continue reading →

Recover from Failed Amazon EC2 Instances

Mohan Cheema — Tue, 09 Aug 2011 14:01:25 +0000

One of the things that’s not immediately obvious about Amazon EC2 instances is that they could fail, in fact Amazon says: It’s inevitable that EC2 instances will fail, and you need to plan for it. An instance failure isn’t a … Continue reading →

Adding more disk space (EBS volumes) to your instance

Mohan Cheema — Wed, 03 Aug 2011 16:04:24 +0000

Adding more disk space (EBS volumes) to your instance The AWS Server AMI comes with an attached 30 GB EBS volume. If you need more space, you can create additional volumes and attach them to your EC2 instance. The steps … Continue reading →

Amazon ELB SSL Termination HowTo

Mohan Cheema — Thu, 21 Jul 2011 10:22:07 +0000

We’ve been using the new Amazon Load Balancers (ELB) for some of our websites, since there’s not much information out there on the subject, I thought a post would be in order. The load balancers are charged at $0.025 per … Continue reading →

Postfix OpenLDAP Courier-imap Amavisd-new SpamAssassin and clamav HowTo

Mohan Cheema — Mon, 01 Nov 2010 16:36:27 +0000

This is a step by step guide on how to configure GNU/Linux system with Postfix, OpenLDAP, Courier-imap, Amavisd-new, SpamAssassin and clamav. Even though this setup was configured on Centos 5, with minor tweaks you should get it working on any … Continue reading →