煤氣公司明火煮食廣告

數天前在網誌談及 ING 莫史迪廣告乃失敗之作，今天在電視上看見高水準的煤氣公司明火煮食廣告。片中找來了一班精靈服從的小狗大展奇技，生動活潑，畫面精彩絕倫。這真是難得的高水準制作，我敢打賭這套廣告必能拿到獎項。

Domain Name Bypass

If one types the IP address assigned to a web server, a default web page should be displayed. I have the idea that a web server which returns a page without the incoming connection passing the domain name might be a security risk, or gives rise to malicious activities. One can easily tell that this is simply web access with domain name bypass. I have seen quite a few web sites which do not allow domain name bypass. One example is www.netvigator.com (IP address 218.102.21.228). If I give http://218.102.21.228/ on my web browser, the remote server return "forbidden access".

Having said that, I am interested to find out how to configure a web server to avoid domain name bypass. Is there anything to do with with VirtualHost Directive ?

Two anti-virus software on a single PC

A couple of days ago I asked an IT friend about why two anti-virus software packages could not be installed in a PC. The answer given to me was that each anti-virus software has some codes resident in memory to protect the kernel and important system files. If two anit-software packages are there, they will clash with each other. This is very much like the case of not allowing two DHCP Servers on a single network segment. I believe the answer really makes logical and technical sense.

無敵金剛莫史迪

最近ING 新推出的一套電視廣告，利用70年代「無敵金剛」主角莫史迪作宣傳題材。直覺上我相信這個廣告將會是失敗之作，因為沒有多少人還會記起這位33年前的莫史迪。如果要找英雄人物作廣告題材，應該選一些不會被時間所淹沒的，例如蝙蝠俠、蜘蛛俠及超人。

WOT plugin for Firefox

WOT plugin is very interesting and perhaps useful. There are many web sites for spreading malware and malicious codes. WOT has a list of dangerous and suspicious web sites based on reputation and the reputation is derived from submissions from volunteers.

I came across a web site believed to be spreading malware. WOT plugin warned me right the way.

Presenting Proper Language Versions of Web Pages to Visitors

Web sites such as www.trendmicro.com and www.blogger.com are built with intelligence to pre-select the languages for display to visitors. If I use English version of IE, the pages are in English text. However, if I use Chinese Version of Firefox, pages in Chinese text are returned. I think this is by means of a front end little Javascript to perform a browser language redirect.

Other than browser language detection, another means is GeoIP database. If the GeoIP detects that a visitor'S IP address is one from China, web pages in simplified Chinese version should be invoked.

200 Mbps residential broadband service

Hong Kong Broadband Network (HKBN) recently introduced 200 Mbps symmetrical broadband service to home users. Actually, the broadband services of HKBN is divided into 10M, 25M, 50M, 100M, 200M and 1000M. I don't think there is a need to divide into some many transmission speed levels. 10M, 100M and 1000M would be more logical steps.

One question I have about 200M service is that Ethernent cards work with 100M and most home PCs are not equipped with a gigabit network card. If a user wants to enjoy 200M broadband service, my logical thinking is that he/she has to buy a gigabit ethernet card.

Intuitively, I don't think users can perceive the difference between 100M and 200M in normal web browsing and email activities. If the broadband connection is used for BT and other bandwidth demanding applications, then it would be a different consideration.

Error in Webalizer

Webalizer is a free software for monitoring web traffic and it can compute hit rates and the number of times individual URLs are accessed by reading the httpd log file. After succesful installation, the first time I run webalizer, there was an error message which said :

"Error: Skipping oversized log record"

On checking the httpd log, there is one long line logged as :

"202.81.182.233 - - [07/Apr/2007:13:15:39 +0800] "SEARCH /\x90\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9x\
c9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\
xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9\xc9.....

This is a worm sending extreme long code targetted at IIS web server. After deleting the long line, everything worked normally. Even if I did not delete the long line, webalizer would simply ignore it.

Telnet server

By means of yum, I installed telnet server, but I forgot how to start it. Hopefully, I recall that telnet daemon is controlled by xinetd. Just run
/etc/rc.d/init.d/xinetd start

will put telnet daemon in service. Of course, it is necessary to tell xinetd that telnet should be enable by "chkconfig" or direct edit /etc/xinetd.d/telnet.

One more trick I made is to change the default port 23 of telnet to other alien port number. This is done by editing /etc/services.

Reverse lookup error

I found the following in my server logs :

gethostby*.getanswer: asked for "7.212.72.222.in-addr.arpa IN PTR", got type "A"
gethostby*.getanswer: asked for "138.0.68.222.in-addr.arpa IN PTR", got type "A"
gethostby*.getanswer: asked for "5.64.72.222.in-addr.arpa IN PTR", got type "A"
gethostby*.getanswer: asked for "148.48.69.222.in-addr.arpa IN PTR", got type "A"

It seems that when doing a reverse lookup, the server expected resouce record to be PTR. However, the system administrator make mistake to specify an A record, causing reverse lookup failure. As far as I can recall, reverse lookup failure might deny email and ftp services. It would be nice if some one can alert the system administrator to report the error.

Browsers supporting International Domain Names

I know for some time that both IE 7.0 and Firefox 2.0 can support International Domain Names (IDN). However, I can not think of any web sites operated by Chinese domain names that can help me to verify this functionality. Until recently, I noticed the domain name http://雅虎中國.cn/ is activated. Yes, by browsing 雅虎中國.cn, it is proved that both IE7.0 and Firefox 2.0 can handling the DNS resolution of IDN. Together with Opera, the three most popular web browsers in the world are capable of handling IDN.

A logical question comes to my mind. Can Safari of Apple do the same ?

HTTP Error Code 403.4

If I type http://www.zurichlifeinternational.com/, the web server has intelligence to return a page which tells me that the web site must be accessed by SSL and a preceding https should be before the web address.



Some people might say it is a clever setting and some might say why bother, just redirect to access the same address by https. I tend to support the latter. For the former, I think it has something to do with redirecting to an alert page upon detecting error code 403.4. Just don't know if this is easy to configure in the server side ?

小事看待

內地遊客購物被騙事件，中聯辦副主任李剛勸喻不可當小事看待。

十三億人民一齊收看行騙過程及手法，這當然不會是小事。還有，特區政府要挽救香港是購物天堂的聲譽，這也不會是小事。

E-Bill

My mobile service provider charged me HK$10 per month for the delivery of printed monthly bill by post. Quite unfair to subscribers since this practice has been in use for many years and no charge was imposed in the past. My subscription plan is HK$58 per month covering 500 minutes air time. The HK$10 surcharge will be equivalent to another 100 minutes air time. It leaves me no choice but to drop the billing by post and revert to billing by Email which in short just simply called as E-Bill.