Friday, May 17, 2013

Outlook - Removing GMail Account from Outlook

Very often, you will want to remove your GMail account from your Outlook for various reason.

To remove GMail account completely. Do the following

1. Open your Outlook. Tools -> Account Settings.
2. At Account Setting, select your GMail account and click on Remove. Click on Yes on the confirmation dialog box.

3. The above steps only remove the account from Outlook. The PST file still exist in the system. So, for XP, you should go to C:\Documents and Settings\your_account_name\Local Settings\Application Data\Microsoft\Outlook. Delete all pst files that has your gmail account name. In this example, it is Please note that you need to show hidden file and folder in your Folder Options before your can see Local Settings folder

4. Empty your recycle bin

Outlook - Accessing and Synchronizing GMail to Outlook

Well.. Many many post in Google had discussed about this topic. My purpose of this post is to provide a tested instruction for my future referral.

The reason to access GMail in Outlook usually are

1. Single point of email access
2. Back up/synchronize Outlook email to and from GMail

In order to access GMail in Outlook, it is best to use IMAP protocol. So, you need to make sure your GMail account has IMAP enabled.

Below are the steps to setup GMail and Outlook

1. Log onto your GMail account
2. Go to Setting -> Forwarding and POP/IMAP. Make sure IMAP is enabled. Click Save Changes after you had enabled IMAP

3. Now, open your Outlook (tested on Outlook 2007)
4. Go to Tools -> Account Settings

5. At Account Settings, click on new

6. A wizard will be shown. Select "Microsoft Exchange, POP3, IMAP, or HTTP". Then click next

7. Click on the check box "Manually configure server settings or additional server types". Then click next

8. Select "Internet Email". Then click next

9. Key in all information as per screenshot. Make sure your user name is

10. Next, click on "More Settings"
11. Click on "Outgoing Server" tab and click on "My outgoing server (SMTP) requires authentication"

12. Click on "Advanced tab". Type in the screenshot information

13. Click OK to close More Settings
14. Click Next and Finish to complete the setup. Then click close to close the Account Settings dialog
15. Now, you should see your GMail Inbox in your mail folder

16. Normally, it will update your IMAP folder automatically. If not, you can right click on your mail box and select Update Folder List

Now, you can access your GMail in your Outlook. You can start doing the following

1. To access your GMail mail, simply click on your folder listed under mail box
2. To move mail from Outlook to GMail, just drag and drop your mail from Outlook to GMail folder.

If you have problem with the setting, you can refer to for the updated list of port numbers and settings

Tuesday, May 7, 2013

DDoS in Action

Not sure if I should be excited, but, this is the first time I am experiencing DDoS on a VPN server. Now, my mind is all about my past infocomm security topic to think about how DDoS works.


The DDoS existed since 1998 and it is happening to me right now. In a nutshell, DDoS means that some adversary is using a BotNet (a large group of computers) to attack a single system to prevent access for legitimate users.

There are wide range of attacking method such as ICMP flood and TCP Syn flood. I will not discuss on the attack as they are widely discussed in Google.


Before my real experience, I always think that DDoS only affect a single system. But now, I know I am wrong.

An DDoS attack to my VPN server caused network congestion to my organization's 10Mbps Internet to slow down. The reason being is the BotNet is sending enormous amount of data in my network, and as a result, the Internet router is overloaded and caused the slow down in Internet as well.

So, if you encounter a sudden slow down in accessing a system or the whole network/Internet, you may be encountering a DDoS attack


First, you need to identify which system is being attack. For me, since I have access to the data center, I physically unplug LAN cable from my router to isolate the problem. And this method helped me to single out my VPN server is being attacked.

After you had identified the system, inspect all logs from the system and identify if you are genuinely under DDoS attack.

If you are under DDoS attack, you can do the following

1. Change the system IP address
2. Set up the firewall to filter the IP of the DDoS attack
3. Set up IPS to detect future DDoS attack
4. And many more if you search Google :)


Big Data - Hadoop Overview

Starting to look into Big Data area and feel that I better look into Hadoop.

Big Data

Recently, everyone talk about big data and I am asking myself what is big data? Big databases and file system?

Gartner define Big Data as "Big data are high volume, high velocity, and/or high variety information assets that require new forms of processing to enable enhanced decision making, insight discovery and process optimization.

High volume refers to the ever glowing volume of data transaction. Data are in petabytes nowadays.

High velocity refers to the speed of processing required to process the data. Time-sensitive data analysis may requires speed of processing of data into seconds.

High variety refers the various type of data. Nowadays, data is not necessary to be structured. Unstructured data such as video stream, mouse click, sensor information, etc... are very common.

So, my understanding to big data is any data that is under the sun.

Why Hadoop?

This is the next question in my mind. Why Hadoop? Organization has been happily using tradition data warehouse and RDBMS to handle "big data" over the decade and RDBMS is proven to be ACID. After some reading, my conclusion is RDBMS is very well designed for structured data and analyzing reasonable size of normalized dataset. These structured data are often stored in a single server that had 1 big harddisk and multiple CPU core.

However, in the current world, 80% of the data are unstructured and distributed globally. In such environment, RDBMS become very inefficient. Some reasons are

1. Moving terabytes of data across system for RDBMS centralized system for data analysis are infeasible
2. Processing these massive data with limited bandwidth and hardware resources at the RDBMS centralized system is very time consuming.

So, if you encounter the above headache with your RDBMS system, it is time for you to consider Hadoop.

Hadoop is
  • Cheap as it can be run on commodity hardware
  • Scalable as servers can be added with required
  • Distributed as no single node store all data
  • Parallel as each nodes run job with their set of data in parallel
  • Suitable to handle massive amount of data that are unstructured and semi-structured
  • Reliable as it replicates data into multiple nodes.
  • Code based as each Hadoop server could run different job code on their specific set of data
  • Network efficient as only processed results at each slave node are sent to master node for result compilation as a whole 
Below are some architectures that I had found in Google that may help to understand more about Hadoop

To archived the above, Hadoop has 2 main components: HDFS and MapReduce.

I need to read more before I had more insight and post about HDFS and MapReduce.


Tomcat - removing server info

Below are the steps to remove Tomcat Server Information 1. Make sure Tomcat is not running 2. Navigate to "Tomcat Installation"...