Archive for March, 2010

domains-in-a-nutshell

About Domain Names – in a nutshell

Mar 31st

Posted by Sridhar in Domains

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A domain name is the address of a website. For example, www.google.com is a domain name and the entire website address – http://www.google.com is called the Uniform Resource Locator (URL).

Top-Level Domains

The “extension” of a domain name is called the Top-Level domain (TLD). So in www.google.com, .com is the TLD. There are 3 types of TLDs – generic top-level domains (gTLD), country code top-level domains (ccTLD) and infrastructure top-level domains.

gTLD

Generic top-level domains are the most popular of all domains. Some of the gTLDs are:

  • .com – originally intended for use by commercial organizations
  • .net – originally intended for use by Internet related sites
  • .org – originally intended for use by non-profit organizations
  • .biz – for use by businesses
  • .info

ccTLD

The country code top-level domains also have the 2 letter country code that is used to designate a country. For example, www.airtel.in is a ccTLD and .in represents India. A list of all countries ccTLD can be found at the IANA Website (Internet Assigned Numbers Authority).

The .IN ccTLD allocation is overseen by a Government of India appointed organization – INRegistry, operated under the authority of National Internet eXchange of India (NIXI). The registration of popular ccTLDs like .IN, .CO.IN, .NET.IN is provided by many organizations. However, to register .GOV.IN, .MIL.IN is exclusively registered by National Informatics Centre (NIC). The ccTLDs .AC.IN, .EDU.IN and .RES.IN is registered exclusively by ERNET.

Infrastructure top-level domains

Infrastructure top-level domains is exclusively used for Internet infrastructure purposes such as in-addr.arpa for IPv4 and ip6.arpa for IPv6 reverse DNS resolution, uri.arpa and urn.arpa for the Dynamic Delegation Discovery System, and e164.arpa for telephone number mapping based on NAPTR DNS records.

Reserved domains

As per the IETF (Internet Engineering Task Force), the following 4 top-level domain names are reserved and cannot occur in production networks within the global domain name system.

  • example – reserved for use in examples
  • invalid – reserved for use in invalid domain names
  • localhost – reserved for use in local computers
  • test – reserved for use in tests

Domain Name formats

  • domain names must be at least 2 characters long
  • domain names cannot be more than 63 characters long, excluding the domain extension
  • domain names can only have alphabets, numbers and hyphen (-). They cannot have spaces, underscore, or any other symbol
  • domain names that are a combination of alphabets and numbers (alphanumeric) are acceptable. For example, www.theysing2me.com is a valid domain name
  • domain names cannot start and end with a hyphen
  • domain names are not case-sensitive, i.e., echopx.com is the same as EchoPx.com

IP Addresses

Along with the domain name, each website also has an Internet Protocol (IP) address. IP addresses are what computers use to connect over the internet. Each computer on the internet has an IP address. The IP address can by a static IP or a dynamic IP. Internet Servers use static IP and computers that you use for connecting to the internet uses dynamic IP. You can find your from www.whatsmyip.org.

IP addresses are regulated by Internet Corporation for Assigned Names and Numbers (ICANN). 209.191.93.53 is the IP addresses of Yahoo.com (type the IP 209.191.93.53 in your browser). When you type a website address in your browser’s address bar, the computer searches the Domain Name System (DNS) which is maintained by ICANN. The domain name is then translated into the corresponding IP address and the computer connects to the website.

Subdomains

A subdomain is a subset of a larger domain name. For example, blog.echopx.com is a subdomain of echopx.com. Even a in domain address like www.example.com, www is the subdomain of example.com. The subdomain www is also called canonical domain names.

Subdomains are usually used either for load balancing or for organizing sites. Websites that have very high traffic, use load balancing techniques to redirect visitors to one of their subdomains like www1.example.com. Others use subdomains to organize their website information. For example, echopx.com is the corporate website, where as blog.echopx.com is used for blogs only and domains.echopx.com is used for online domain name registration.

Registering Domain Names

A domain name is registered by a registrar. The registrars are appointed by ICANN. All domain names are registered with the ICANN registry.

A domain name is registered for a specified period of time, i.e., from 1 year up to a maximum of 10 years at a time. The domain name registration fee is usually charged on an yearly basis. You can continually use the domain name by renewing it within the specified time limit. If you do not renew it within the specified time, it will expire and will be available for anyone for registration.

Domain name expiry, grace period, retrieval

Whenever a particular domain name is not renewed till the expiry date, it would slip into the Renewal Grace Period. During this period, any website and mails associated with the domain name would become non-functional. Renewal Grace Period are different depending upon the domain name extensions. For example, .com, .net, .org, .biz, and .info have 40 days renewal grace period, where as, .in has only 15 days. A .eu domain name does not have any grace period. If you do not renew the domain name even in the Renewal Grace Period, then the domain name would be deleted and the domain name will go into Redemption Grace Period (provided there is no back-order for this domain name) and you would get a chance to redeem it.

Redeeming a domain name is expensive, time consuming and generally a manual process. It can take up to 5 working days to redeem a domain name. The Redemption Grace Period is generally of 30 days after the domain name is deleted and during this period, only the current Registrar of the domain name can redeem the domain name. If the domain name is not Redeemed during this period, then it would move to the Pending Delete period for 5 days. In this status, the domain name can not be Redeemed and after this period, the domain name would be available for fresh Registration.

Domain pointing

During the domain name registration process you will be asked where you want the domain name to “point”. This is the IP address of the server where your web site will be located and there should be a primary and secondary server. You can obtain this information from your web hosting company. There may also be a listing for other optional servers. The registrar may provide the IP addresses of at least two delegated name servers on their site. You can change this if you have your own. It can also be changed at any time later if you change servers. It can take 48-72 hours for your domain name to be set-up and available on the web.

Summary

While a domain name is nothing more than an alias for the IP address, it is increasingly becoming a very important tool in marketing your website. Being aware of what it is and how to keep it secure is crucial. Read our earlier article on how to protect your domain name. If you have any specific questions / comments, do post it here.

Drupal

Slideshow with Drupal Views Cycle module

Mar 29th

Posted by Sridhar in Drupal

13 comments

DrupalViews Cycle is a nice module that uses the jQuery Cycle plug-in to provide image slideshow with many different types of transition effects. In Drupal, you are going to create a content type to upload images, generate a view for the uploaded images and style it with the Views Cycle module. The module also provides with many variable settings that you can set. [For Drupal 6]

Requirements:

Installation:

  1. Download and enable CCK & Views modules. To allow image upload, also add imagefield module. Imagecache is optional.
  2. Download views_cycle and the jQuery cycle plugin. The jQuery cycle plugin also includes a javascript file – jquery.cycle.all.min.js. Copy this file into the views_cycle module directory and rename it as jquery.cycle.js. Now, enable views_cycle module.

Create content type:

  1. Login as admin and go to admin/content/types and click on the Add content types tab to add a new content type
  2. Give a Name to your content type and enter the machine-readable Type. For example, Name – Animation and Type – cycle_anim
  3. In Submission form settings, remove the body field
  4. In Workflow settings, uncheck Promoted to front page
  5. In Comment settings, set it to Disabled
  6. Click on the Save button
  7. In the Content types list page, click on Manage fields for the new content type that you have created just now
  8. Add a new field with Label as Image and Field name as field_anim_image
  9. Under Select a field type, select File and in Form element select Image. Click on Save button
  10. In Permitted upload file extensions, enter values as png gif jpg jpeg
  11. Under Global settings, check the Required checkbox and set Number of values to 1. Click on the Save field settings button
  12. Click on the Display fields. And under Teaser, select Image and under Full node, select Image linked to node

Create content:

  1. Browse to node/add and click on the Animation content type to add images for the animation
  2. Create at least 2 nodes with different images

Create view:

  1. Browse to admin/build/views/add
  2. For View name, enter Animation and set the View type to Node. Click Next button
  3. Click + (Add) button under Fields and select Content: Image (field_anim_image). Click the Add button
  4. Set the Label to None and under Format, select Image linked to node. Click on Update button
  5. Click + (Add) button under Filters. Select Node: Published and Node: Type. Click on Add button
  6. Under Node: Published configuration settings, set it to Yes and click Update button
  7. Under Node: Type configuration settings, for Is one of, check Animation under Node type. Click Update button
  8. In the Basic settings group, for Style, click on Unformatted link. Set the default to Cycle and click Update button
  9. Under Default style options, set the various values for your animation. You can come back to the view and change the values later.
  10. Now you can add a block view or a page view for your animation.

With my animation, the Views Cycle out put the animation with images put in unordered list and default padding on the top and left sides of the container. One way to fix this is through your CSS. Though this module is simple and very nice, there are other variations for slideshow / carousel / rotator with many more features like the DD Block (http://drupal.org/project/ddblock) for Drupal. Have a look at the comparison here http://drupal.org/node/418616.

[This article is for Drupal 6]