Live Free. Live Happy.

Author: rahul

  • Shutdown Using Power Button

    Here is a small tip. For configuring the power button to start shut down sequence when pressed, install “acpid” daemon via apt. This will install the necessary event (/etc/acpi/events/powerbtn) and associated action (/etc/acpi/powerbtn.sh) to be performed upon pressing the power button.

  • Setting up DHCP Server

    A dhcp server allows you to assign IPs dynamically to your clients. For further information visit, Setting up DHCP server.

  • Connecting via PPPoE

    This is especially useful for those who use a username and password to connect to their broadband cable/ADSL connection (such as that provided by BSNL, Airtel and Tata Indicom). For this you need to install pppoeconf package and run the command.

    # apt-get install pppoeconf
    # pppoeconf

    Alternatively, if you are using mepis you can configure by going to Kmenu –> Internet –> Connection –> ADSL/PPPoE configuration.

  • Setting up Linux Gateway

    Using this, you can set up your linux pc as a home gateway for all the other systems. For instructions on how to do this, you may refer the below links:

    Iptables Tutorial (look at the the Example Scripts)
    Using Linux iptables or ipchains to set up an internet gateway / firewall / routerfor home or office.
    Setting up a Linux Home Gateway

    Please note to disable any other firewall services (such as Guarddog) if you are using your own custom rules or else the firewall will not work as expected.

  • About SSL/TLS

    SSL/TLS enables you to communicate securely with your server. Most of the major protocols such as http, smtp, pop3, imap can use SSL/TLS. While TLS can be used over the same port, SSL has to be run on a different port such as https, smtps, pop3s, imaps. SSL has been superseded by TLS. You can find more information about SSL/TLS on Wikipedia.

    StartCom Free SSL Certification Authority and CAcert.org are two CAs which issue free certificates.

  • Dynamic DNS

    Dynamic DNS enables mapping of a dynamic IP to a fixed domain name. This is especially useful if you connect using ADSL services such as those of Tata Indicom, Airtel or BSNL as they provide a dynamic public IP every time you connect to the Internet. A public IP is a IP to identify the machine in the Internet (in contrast to private IP which is limited to intranets). Again both public IP and private IP can each be either static or dynamic.

    While having a static public IP makes it easy to access your server on the Internet, static public IPs are costly. But using dynamic dns service, we can map a fixed domain name to a dynamic IP thereby making the server accessible just as in the previous case. Some of the services which offer free dynamic dns support are:

    While the first two services DynDns and No-IP are more popular, please note that the free version of their services enables mapping of only certain fixed sub-domains. If you want to map your own custom domain to a dynamic IP, then you shall have to purchase their premium service.

    But the last service zoneedit offers even this custom domain name mapping for free. It also has a very extensive DNS records management tool. The only limit is the maximum number of free zones you can add to their system is limited to five (even if you add and delete one zone you lose one credit and are only left with the ability to add four more zones). But for individuals and SOHO, this should be more than enough.

  • Pinnacle-to-go Review

    Website: Pinnacle-to-go

    I had purchased the Pinnacle-to-go USB TV Tuner Card about a year back here in Secunderabad, India. Pinnacle is supposed to the best company for TV Tuners card (at least among those available in my city). But I am disappointed with it. The TV works fine but the video cassette to DVD conversion was not that great. I had some video cassettes but when I connected the video player to the laptop (via the composite input), the playback video quality was just average and hence the recorded quality also was average. I definitely expected it to be much better because of the brand name. Also I have had a lot of problems in trying to make this device work properly in linux. Also one thing to note is that the PCTV Media Center which came with it is now outdated. The latest PCTV viewing product is called “Pinnacle TVCenter Pro” (can be downloaded from Pinnacle Site).

    To summarize, among the features which I used, TV viewing and recording is decent but quality of playing back via the composite input was poor. If you are looking for TV viewing, then you may consider buying this. But if it is for video capture (especially good quality), then I’d suggest you look at other products from Pinnacle. Also last but not the least, be sure to read as many reviews as possible before you purchase any TV Tuner / Video Capture Card.

  • Comptia Network+ Certification Resources

    Comptia is a certifying authority. One of its exams which I had given and cleared in April 2006 was the Comptia Network+ Certification. I wasn’t planning to take it. But as I was anyway reading a book on Networking Basics (which actually was a guide to Network+ Certification exam), I decided to take it. And I should say the book which I went through (All-In-One Network+ Certification Exam Study Guide Second Edition With CD, Indian Edition) is an excellent resource for learning Networking basics. Below is the errata for the book (note that this has not been validated by anyone else). I couldn’t contact the author for sending it and they might have been fixed in the later editions. Anyway, here it is:

    – In Page 366, (Chapter 12 -> Under “Windows 2000” section), it is metioned “Windows 2000 only supported TCP/IP natively, although through extra configration it supported NetBEUI, IPX/SPX, and AppleTalk”. This is contradictory to the answer given for Question No. 9 which states that “TCP/IP and IPX/SPX are native on a Windows 2000 syster. NetBEUI comes with 2000, but you must install it”
    – In Page 503, (Chapter 16 -> V standards), the speed for V.34 is mentioned as “28,000 bps”. It should be “28,800 bps”.
    – In Page 507, (Chapter 16 -> ISDN), it is mentioned “ISDN PRI only provides a single B channel for a total throughput of 64 Kbps”. But as per information on the internet an ISDN PRI provides 23 B channels and a D channel with a bandwidth of 64 kbps.
    – In Page 513 (Chapter 16 -> Satellite), it is mentioned “Neither cable modems nor satellite use PPP,PPPoE, or anything else that begins with three Ps.”. But PPPoE can be used over a cable modem.
    – In Page 518, (Chapter 16 -> Copper Carriers: T1 and T3), it is mentioned “There are also E3 lines, which are similar to T3 lines, with a bandwidth of 45 Mbps”. But the bandwidth of E3 lines are 34.368 Mbps.
    – In Page 592, “SFU” is written as “FSU”. This is a typo.

    Apart from that book, here are some other useful links:

    Comptia official site
    ———————

    http://www.comptia.org/certification/Network/default.aspx

    Free study guides (I managerd to cover only first three)
    ——————————————————–

    http://certiguide.com/netplus/index.htm – This is a free complete online Network+ study guide which also includes real world exam questions
    http://www.examforce.com/customer/special14.php – This free study guide was advertised in the official comptia site itself
    http://www.techexams.net/technotes/networkplus/pdf.shtml
    http://studynotes.net/indnet.htm
    http://www.cramsession.com/certifications/products/product-details.asp?product_id=10030&product_type=study+guides

    Free sample questions
    ———————

    http://www.bestsamplequestions.com/network-plus-sample-questions/network-plus-sample-questions.html
    http://www.simulationexams.com/SampleQuestions/net_q1.htm
    http://www.thecertificationhub.com/networkplus/networkplus_test_bank.htm

    Brief overview revision study guides (Cram notes)
    ————————————————–

    http://www.mcmcse.com/comptia/network/N10003guide.shtml
    http://www.examguides.com/network-plus.htm
    http://www.jamesgibbon.com/nplus/basic.html
    http://www.riguy.com/net+.html

    Free practice tests (online) (in decreasing order of relevance according to me)
    ——————————————————————————-

    http://www.comptia.org/certification/network/samplequestions.aspx
    http://www.techexams.net/co_netplus.shtml
    http://www.passitnow.com/comptia.html
    http://pages.prodigy.net/aplus_omega/net1.htm
    http://www.cert21.com/N10-002.htm
    http://www.exampractice.com/certification/comptia/networkplus/
    http://www.cram4exams.com/exams/net+.shtml
    http://www.cram4exams.com/exams/net+2.shtml
    http://www.freepractice.com/network_plus/network_plus.htm
    http://www.mcmcse.com/forums/exams/questions.php?id=17 (I couldn’t get to log in here)

    Free practice tests (software)
    ——————————

    http://www.examforce.com/customer/special13.php
    http://www.preplogic.com/products/exams/download/550/setup.exe
    http://www.ucertify.com/exams/CompTIA/N10-003.html
    http://www.vnpublishing.com/netplusdownconfirm.htm
    http://www.simulationexams.com/downloads/comptia/network+download.htm
    http://www.studyhallsoftware.com/Demoexams/NetplusTests.exe
    http://www.selftestsoftware.com/demo/default.aspx [this has only 5 sample questions]

    Pages which have links to the above resources (this pages are essentially collection of the above sites)
    ——————————————————————————————————–

    http://certification.about.com/od/comptiaquestions/
    http://www.certification-crazy.net/network_study.htm
    http://www.certguide.com/networkplus.asp

    References
    ———-

    http://www.tcpipguide.com/free/t_toc.htm
    http://compnetworking.about.com/od/workingwithipaddresses/l/blip.htm

  • British Library Hyderabad Review

    Most of you must have heard of the British Library. I had been its member for one year. I had taken the Rs.1600 plan (this is the plan under which one I could rent DVDs). But I must say that I have been thoroughly disappointed. While I cannot comment on all the facilities provided by British Library, I must say that the DVD rental facility is pathetic (at least as of the day of writing this post). The DVDs available are really outdated. Out of those which I borrowed, 50% of them were not readable. Moreover only one DVD can be borrowed maximum at a time. This proved to be very disadvantageous to me as I don’t stay close to British Library and it wasn’t feasible to visit it often. And you could easily imagine my frustration when even this one DVD didn’t work many times. So my advice is if you plan to rent DVDs you should be better off using your local video library or subscribing to an online DVD service such as Catchflix or Bigflicks. Also I once tried to borrow a book “The World is Flat”. The waiting period for the book was 4 months. Though I have not ever borrowed any other books, I anticipate this is the case with most of the recent best sellers.

    But British library might be a great place if you plan to visit regularly as it has a large collection of magazines and books. Apart from this, many events are regularly organized by British Library. So depending upon what you plan to use the British Library for and how frequently you plan to visit it, take the membership.

  • A Dussera + Diwali + Thanksgiving + Christmas Gift …

    And that would be a USB to SATA/IDE cable … hee hee. About three months back I purchased an external 250 GB SATA hard disk. But as I wanted to use it for backup purposes I did not want to fix it inside the cabinet but keep it outside and access it via USB. For this purpose, I purchased an external SATA to USB enclosure from CTC, Parklane, Secunderabad and started using it. But soon I realized that it was hanging intermittently and the only way to access the hard disk again was switching off and switching on the USB enclosure. A similar drive brought by someone I know had corrupted his entire hard disk. What is worse is that these cheap quality USB enclosures available in CTC do not come with any warranty.

    This is when I decided I would order one from US. And my friend Sagar offered to buy me one. There are many USB to SATA/IDE cables available for ordering online. The one I got was from Granite Digital. Though this was a bit costly, I decided to go for it as it exclusively mentions support for linux. Another such cable which has got good reviews is the one from Vantec. Be sure to check out the reviews on the Internet before you buy any such cable / enclosure as a low quality one might corrupt your hard disk and cause data loss.

    And as to why it is a Dussersa + Diwali + Thanksgiving + Christmas gift, is because I had almost waited for 3 months for someone to get this to India from the US and during this period, all those festivals passed by. Thanks Sagar for this gift. It is a life savior.