Use less bandwidth

What shall average end users do in times of severe Internet disruption. I can figure out several ways to help :

1. Stop using P2P software;
2. Configure email client to use plain-text instead of html (html-based contents involve unnecessary bytes which are for cosmetic effects);
3. Do not access streaming videos site such as video.google.com and youtube.com;
4. Do not use ftp services;
5. Do not attach files in email;
6. Do not use VoIP phones;
7. Do not use web cam in MSN.

You may argue these are crazy ideas. But think carefully, if everyone use less bandwidth in times of crisis, we can still maintain the most essential Internet communication services.


Life without Internet

This is the first time I successfully connected to blogger.com after the earthquake in Taiwan on 26 Dec. I have tried many times but the browser just returned nothing. Over the past 2 days, we were isolated from other parts of the world. I finally experinece how diffcult life is without Google, MSN, Yahoo and their webmail service.



Today, there was a Christmas greeting message in my wife's inbox. We did not know the sender. Worst still, the message said there was a personalized e-card attached in a zip file. I checked the zip file that it contained a single file called postcard.exe. This surely was a Trojan horse or malware. To play safe, I had instructed my wife and my son not to open all attachments from someone they did not know.


Carrier Grade DHCP Server

DHCP severs can not achieve a high availability of 99.99 % without the use of stand-by server with automatic failover. For hot standby, there is a design or perhaps network architecture problem that only one single DHCP server can be placed in a network. What I know is that this problem has been tackled by IETF by developing the DHCP Failover Protocol. It works this way, a main server is keep communicating with the standby server about the IP adresses allocation and the standby server will not lease IP addresses to host. When there is a problem in the main server, the standby server will automatically take over and the previously addresses allocations by the main server before failure are known. This seamless takes over can ensure the provision of carrier-grade DHCP Server.


HKDNR offers one .hk domain free for a year

HKDNR asked me to fill a customer satisfaction surey. It promised to offer one single .hk domain to the 1st 100 submitters responding to the survey.

I think I am amongst the quickest to send back the suvery form. Just now thinking of which .hk domain should I use !! Yes, I got it, simple get warrenkwok.com.hk or warrenkwok.hk. The results will be made known to me by early Feb 2007.


Mail Server and Reverse DNS lookup

It has been reported that some mail servers fail to deliver outgoing emails to other servers due to the lack or incorrect settings of reverse DNS lookup.

I try to recall my experiences about the settings of MX and PTR in DNS configuration. Woo, the IP address of the mail server should have a proper PTR record which upon interrogation, shall point to a particular hostname. The PTR does not need to be the same host name or use the same domain as the MX record. However, it does need to point to a hostname that has an A record pointing back to the same IP address.


Poor Performance of IE 7.0

Damn it. IE 7.0 is really slow in performance in browsing web pages. Perhapas, this might due to the interrogation of phishing database set up by Mircosoft prior to allowing the client browser to directly go to an individual sites. Hey man, I don't need phishing protection. The reason is I never click on links embeded in email messages which require the input of personal information. I will disable the anti-phishing feature in IE 7.0.

Another disappointment is that when ActiveX is invoked, IE 7.0 broswer hangs up occasionally. IE 7.0 and ActiveX are from the same vendor Microsoft. There should have been extensive testing on compatibility before releasing out. I just hope Microsoft can release the patches to bring IE 7.0 in a proper working condition.


Changing hostname of a server without reboot

I need to change the hostname of my server. This is normally done by editing /etc/hosts. However, the new hostname will not be effective or placed in memory without rebooting. Fortunately, the command "hostname new_hostname" help me to solve this problem. The purpose is to set a overriding hostname in memory until next time the server reboot. This feature reallys help system administrator a lot.


MOOV on 3G platform

The success of 3G mobile phone to enter the mass market hinges on content. Everybody has heard "Content is King". The lack of content is the main reason people do not like to use 3G mobile phones. PCCW might be able to change this. It has integrated MOOV, the biggest online music store with its 3G platform. That is to say, people using PCCW 3G phones can listen to their favorite music delivered from 3G platform while on the move.

I will NOT rush to subscribe to this service. It is better to wait and see how the market responds to this new development.


Bounce Spam

I have done some analysis on bounce spam.

Actually, the spammer sending out the spam has used the victim's email address as the sender and the spam message is purposely send to a non-existing users of a mail server. This is done by froging the "To: and From" fields in the email message. Since there is no such user in the receiving mail server, the mail server will perform its job to bounce-back the spam message to the email address in accordance with the "From:" field of the spamming message.

Bounce spam is a new technique not used in the past. It is found quite recently. The single purpose of using this indirect method is to circumvent anti-spam systems. Spammers know very well that IP addresses of compromised hosts, open relays and zombies are often listed in blacklist systems or can not get through reputation-based anti-spam engines .

Bounce spam is NOT effective since many users will just simply delete messages from their INBOX which say messages "Non-deliverable" or "User-Unknown". Those caring users will open and see what happen. However, it is still a valid and perhaps guaranteed means of dropping a spam message to the target recipient instead of directly sending out from open relays, compromised hosts or zombies which has a high chance of being blocked.


Election Results

It has been announced that all representatives of the pro-democracy camp for the IT Sub-sector have secured a seat into the Election Committee. This is a great news since I have casted my votes to the correct candidates. The most interesting thing is that all the 6 candidates (working level IT people) of ITVoice won their seat.

The turn-out rate in the IT Sub-sector is the highest of over 45 %. Perhaps this is due to the Richard Li's effect.

Charles Mok got 1128 votes, the highest in this sector. That's why I always say this guy never disappoints me.






Bon Jovi Live from London Concert

From Youtube.com, I saw some video clips of Bon Jovi's Live from London Concert dated back to 1995. Amazing, this is the best Bon Jovi's live concert I have ever seen. The concert started with the song "Living on a prayer". In the middle of the concert, Bon Jovi suddenly announced that they kicked Michael Jackson out of No.1 in the radio chart. This triggered over 70000 audiences on the floor to applauded loudly.

Without hesitation, I decide to get one such DVD from HMV.


loading new zone records without restarting named daemon

I have been finding solutions for some time how to load newly created zone records into memory without restarting named daemon. Yes, the answer is "rndc reload". A single zone can be loaded without affecting other working records like "rndc reload abc.com".

Next time, when there is a change in zone files, I will use "rndc reload" to replace "named restart" which is a bit handy.