My trip to Egypt

I returned from Egypt after 10 days of visit. Any things unforgetable. Not so much. Pyramids, Sphinx, tombs and ancient temples were all great but not unforgettable. If I have to choose, I would say the sun set scenery in River Nile was very beautiful and my personal experience of seeing mirage in desert was fascinating. Take a look at the pictures below.

Sunset of River Nile

Mirage on Desert


Bon Jovi's song appears in BC31

I heard that Bon Jovi's song "You give love a bad name" is picked in BC31. I have predicted this quite some time ago.

How many songs of Bon Jovi are in BC series ? I count to five, i.e. runaway, always, living on a prayer, blaze of glory and you give love a bad name.


Year 2038 Problem

When I look at the calendar function of Openwebmail, the year field is up to year 2037 only. This reminds me about 32-bit Unix/Linux operating system that uses a 32-bit register to store the number of seconds lapsed since 1 Jan 1970. The latest year shall be 1970 + (2^31 / (24 x 3600 x 365) = 2038.

In other words, my server will not work after year 2038. Nothing can be done but there is no worry at all. I bet by Year 2020, all computer systems on earth will be based on 64-bit architecture.


Maximum size of a blog message

Surprise ! I accidentally find out the maximum size of a blog message in blogger.com is 1MB. Google is too generous. This is really an over-provisioned parameter. I guess I probably need up to 5 KB only.


Celebrating the 40th anniversay of Internet

This year marks the 40th anniversay of the Internet.

Are you kidding ? How come Internet has been around for 40 years ?

That is true. Internet was evolved from APARNET and APARNET was set up in 1967.

What can we expect at the 50th anniversay of Internet ? Well, I guess each household will have gigabit of bandwidth in use. All electronic devices, whether fixed or mobile, will be on IPv6 and hooked up to the Internet. There are many more to expect ....


Think about HTML email clients again

From day one onwards, I support text-based email clients as opposed to HTML-based counterparts. In the light of spamming activities, Internet fraud and spreading of malicious software, it is good time for users to think about this question again. There are a lot of risks with HTML email clients. I just name the apparent one:

1. HTML-based clients can download malicious software in background once an email is opened.
2. Phishing and identity theft are all done on HTML contents.
3. Spammers can track if the recipient email address is valid because the URL links can embedded the recipient address and send out to the spammer's host automatically.

Apart from security concern, there is the supporting argument HTML emails increase the byte size and occupy more bandwidth due to cosmetic effect. However, these days, with large bandwidth available and huge hard disk space, will anyone care about this.


DoCoMo's 4G Trial reached 5 Gbps

In future, what speed can a 4G base-station offer ?

According to the news sent to me by Telecom Asia, using a 100-MHz channel, the downlink speed was tested to be 5 Gbps. This high speed was aided by 12 sets of MIMO transmit and receive antennas and proprietary received signal processing technology.

For those working in the spectrum side, they will ask for spectral efficiency. This translates to 50 bps/Hz (5000 Mbps/100MHz).

Hey, wait a minute, how can we expect to have 12 receive antennas in end-user mobile devices. Where comes the 100 MHz spectrum, in what bands. Honestly speaking, users will be quite satsified if they could have 100 Mbps in full mobility at affordable price. There is still a long way to go.


.com or .net

My friends asked me why I decided to change my domain name from ending with .com to .net. I said that .net got a higher status. I have all the services of my own needed to be a .net which include email server, web server, dns server, ftp server and secure shell server. It will be logical for me to have a .net domain name than a .com domain name.


Root Server Attack

My colleague told me the news reproted in Metro news related to root server attack two days ago.

This time, DDoS attackers successfully struck down "L" and "G" root servers plus one .org TLD nameservers. One of the root server hit down is operated by US Department of Defense in Pentagon. The attack lasted for 12 hours. However, there was no noticeable interruption to the Internet service.

Given there are now over 90 root server mirrors all over the world backing up the original 13 root nameservers by anycast routing, there is no chance of bringing down the entire root domain.


An email from Samson Tam about CE Election

Here below is an email from Samson Tam I received this morning.

According to the survey conducted by Mr Samson Tam, 40 % of voters support Mr Leong. Applying this percentage, Mr Leong could be able to secure 320 votes in the CE Election. Isn't it amazing ?

"Dear friends of the IT sector,

Since my email sent to all of you one week ago seeking your views on nominating the CE candidates, I have received 420 replies out of thousands of questionnaire emails. I thank all of you for enthusiastically expressing your views and responding my quest.

Of all the replies, 230 were of the view that I should nominate Mr. Tsang, whereas 171 considered that I should nominate Mr. Leong. Four of them suggested that I should not nominate both, while a dozen of them expressed other suggestions, or not at all. As such, in accordance with the survey result, I will nominate Mr. Tsang in the coming CE election.

Through this survey, I have learnt more about the industry, the different voices and demands of the IT practitioners, and have got many valuable views and suggestions put forth by many of my friends in the IT sector. Overall, it seems that many IT people are longing to see an election with competition. Also, they are willing to actively participate in it, so as to contribute to a better IT future.

Once again, I would like to thank all of you for your active participation in the survey and feedback.

Best regards,

Samson Tam"


A story about firewall

This is a true story.

A large corporation in Hong Kong is using Checkpoint Firewall on Windows 2000 Server as a software firewall. My first thinking is that Windows 2000 Server is not a hardened server OS. How could one rely on a non-hardened server OS to build a mission critical application on top of it. The second thinking I have is that patches for Windows OS are released as frequent as several times a month. When patches are added, the server has to be stopped and re-started. Testing would be followed to check if the added patches will create new problem. The third bad thing is that Windows Server requires periodic reboot, unlike Unix or Linux which do not require re-boot after running for two to three years. This results in some loss of availability. Having said that, I could not imagine how this application can offer 24 x 7 x 365 non-stop service.


Is vsftpd really secure

People call "vsftpd" very secure ftp daemon. There is one default setting which renders the daemon insecure. When a user login, he can leave his home directory to go up to other directories. There should be some locking mechanism to ban this. Googling around tells me that by adding the following line in /etc/vsftpd/vsftp.conf can overcome the problem:


This way, ftp users are locked in a jail.


Goodbye to WS FTP

I had used WS FTP for more than 10 years. A few years ago, Ipswitch announced that WS FTP was no more a free software. Since then, I had not any new release.

Frankly speaking, the WS FTP I had in hand was quite outdated. It did not have the drag and drop function to partially transfer files in folders between local and remote machines. When large number of files were transferred, it hang up occassionally.

I made up my mind to say goodbye to WS FTP. What would I like to use then ? I should go for Smartftp client. It is a bit strange. Normally, remote machine will be on the right side but Smartftp client makes a different direction. It is just a matter of time to get used to the new screen layout.


Yoga and Information Security

I find one common feature between Yoga and Information Security.

Yes, it is "insight that brings strength and agility". Agree ?


IIS under construction

If you are a system administrator and you have started the IIS server but the web pages are not ready, it is important to put an index.html something like "This site is currently under construction". If not, look at the screen below. It tells people that you are using Mircosoft IIS Web Server. This is a vulnerability to disclose the server and web OS to visitors.

I must blame Mircosoft for this silly fault. In the absence of a default page, the web server can just return a 404 error code of page not found. It is much safer than revealing the server and web OS.


acrobat PDF reader eats up 32MB memory

Using task manager, I noticed that acrobat PDF reader consumed 32 MB of memory. This is a huge amount of memory resource. Besides eating up memory, I don't think acrobat PDF reader can give a good performance.

I have switched to use Foxit pdf reader. This software can load and open PDF document really fast and it only takes up 4 MB of memory, just 12.5 % of that of acrobat pdf reader. Of course, it is a freeware.

I regret that I only discover this great software so late.