Combat Marathorn Class

Tonight I joined the Combat Marathon Class at Mong Kok which lasted for one hour and fourty five minutes. There were all together 18 tracks played, of which three were for Muay Thai. This class was of course a high intensity exercise. I believed I had burnt over 1300 kcalories.

About the class arrangement, only 120 members were allowed. Up to 15 members from each club could be allowed.

One thing I didn't like was there was no need to do the push-up conditioning after the 9 track. Doing the push-up made our body temperature dropped and our heart-rate also slowed down. It took a while to get back to the best shape. Just a waste of time !!!!

How to dial to an IP Phone

I got a business card in which there is an IP Phone number printed as follows :

IP Phone : 202.122.98.88 (P2P)

I wonder how I can use Internet to dial and connect to this IP Phone. My colleagues suggested that I should use Netmeeting in which the p2p Internet phone is H.323-based. I still can not figure out how to proceed.

Suggestions to Les Mills

This is my third suggestions to Les Mills on Body Combat tracks :

Artist : DJ Moore
Track : Smoke on the water
Reason : The rock music is good and the beat is strong for Muay Thai. Just re-use it for Muay Thai track in new releases. I can expect the same effect as the re-use of "We will rock you" in BC30-7.

Having seen the success of re-using past tracks in BC30 (track 2, 3 and 7 in BC 30 are re-used tracks), I am sure combat fans will be addicted to this track.

I very much hope Les Mills will take my suggestion.

PCMCIA LAN card will become history

Today, I went into a computer shop to ask for a PCMCIA LAN card. The sales staff were puzzled wondering what kinds of notebook I had which did not have a built-in LAN card. I told them that some people who conduct network testing and monitoring need two or three LAN connections in their notebook PCs. The sales people went on to tell me that they only had one such card sold out in a year.

One thing for sure is that PCMCIA LAN cards will become obsolete in near future. I like to keep this kind of hardware devices and I will buy two more for future use.

whois search

I needed to look for the allocation of the IP address 66.179.240.29 and found out the owner. This was an IP address under allocation of ARIN. Obviously, I would use the web site of www.arin.net and doing a web-based whois search. Quite strange, the information could not be found.

Intutively, I had the feeling that web-based whois search is not as reliable as whois client directing interacting with the whois database of ARIN. On a Unix shell, the command to be invoke is :

$whois 66.179.240.29 whois.arin.net
[Querying whois.arin.net]
[whois.arin.net]
Inflow Inc. NFLO-AR-3 (NET-66-179-0-0-1)
66.179.0.0 - 66.179.255.255
PBase.com, LLC INFLOW-996-94320-16484 (NET-66-179-240-0-1)
66.179.240.0 - 66.179.240.127

# ARIN WHOIS database, last updated 2007-01-21 19:10
# Enter ? for additional hints on searching ARIN's WHOIS database.

Yes, really. It worked which indicated web-based whois could not provide reliable information.

Satellite killers

China has not made any official announcement about the purpose of testing ballistic missile destroying an obsolete weather satellite in orbit. I think this is a show off ! Yes, indeed, China has sent a clear message to the world, especially to the US that she has the technology required to hit down orbiting satellites in outer space.

As Chinese citizens, we have nothing to be proud of for such technological achievements. Do we really need such a weapon for defence ?

New Blogger account

I have migrated my old blogger account to the new account. Not many changes are visible. I only spot two good features. First, there is a label which users can tag on the message. I think it can help to manage and display different messages according to category.

The second feature is very good, instant publishing. Whenever I publish a new post or change settings, my blog is updated. There is no need for me to republish after changes.

file limit

I have about 23000 files in a single directory. If I try to use mv, rm or zip *.* for files in the directory, there is a prompt of argument too long. This sends a clear signal to me that there is a limit on the number of files mv or rm can work on. I am interested to know this limit. How can I find out ?

root name service available in HKIX

When accessing APNIC web site, I noticed that HKIX has set up a mirror site for the f root name server (f.root-servers.net). This can dramatically boost the performance of root DNS service for Internt access in Hong Kong. The presence of the root mirror service can be detected by using a traceroute command as :

# traceroute f.root-servers.net
traceroute to f.root-servers.net (192.5.5.241), 30 hops max, 38 byte packets
1 kreisler.netfront.net (202.81.252.28) 1.156 ms 1.838 ms 2.693 ms
2 isc1-FE.hkix.net (202.40.161.202) 2.766 ms 2.235 ms 3.203 ms
3 f.root-servers.net (192.5.5.241) 2.879 ms 3.305 ms 3.336 ms

Yes, indeed, the next hop after HKIX is f.root-servers.net

iPhone

These few days, people I know are all talking about iPhone. Can you resist the temptation - a smart phone with no keypad, 4GB storage and all iPod-enable features. As a die-hard fan of iPod, I think I will get one. It is not good that the phone will only be released to the Asia market by 2008.

The stock price of Apple Computer Inc has risen by 2.5 % after iPhone is unveilled.

VirtualHost in Apache

Just when I thought I was competent about various settings of virtual host in Apache, I encountered this error when adding a new web site :

"Starting httpd: [Wed Jan 10 19:43:20 2007] [warn] VirtualHost http://www.bya.org.hk/ overlaps with VirtualHost http://www.amrita.org.hk/, the first has precedence, perhaps you need a NameVirtualHost directive"

The result was that access to http://www.amrita.org.hk pointed to www.bya.org.hk.

I had to add the NameVirtualHost 202.81.252.116:80 in "httpd.conf" to make things work again.

ORDB closing down

ORDB announced that their open relay database running as DNSRBL will be closing down since 1 Jan 2007. This is a sad news and I have been relying on ORDB.org to kick out spam email by relay. One important development as seen from the closing down is that spammers have changed their tactics and open relay RBLs are not the most effective way to counter spam, Here below is the announcement before the closing down of their web site :

"We regret to inform you that ORDB.org, at the ripe age of five and a half, is shutting down. It's been a case of a long goodbye as very little work has gone into maintaining ORDB for a while. Our volunteer staff has been pre-occupied with other aspects of their lives. In addition, the general consensus within the team is that open relay RBLs are no longer the most effective way of preventing spam from entering your network as spammers have changed tactics in recent years, as have the anti-spam community.

We encourage system owners to remove ORDB checks from their mailers immediately and start investigating alternative methods of spam filtering. We recommend a combination involving greylisting and content-based analysis (such as the dspam project, bmf or Spam Assassin)."

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.

postcard.exe

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.