The functionality of a domain name is to provide recognizable names, to mostly numerically addressed Internet resources. This abstraction allows any website to be moved to a different physical location in the address topology of the network, in effect changing the IP address. This translation from domain names to IP addresses is accomplished with the global facilities of Domain Name System (DNS). By allowing the use of unique alphabetical addresses instead of numeric ones, domain names allow webt users to more easily find web sites and any other IP-based communications services. The flexibility of the domain name system allows multiple IP addresses to be assigned to a single domain name, or multiple domain names to be services from a single IP address. This means that one server may have multiple roles (such as hosting multiple independent websites), or that one role can be spread among many servers. One IP address can also be assigned to several servers, as used in anycast networking.
Tuesday, June 9, 2009
Domain Name
The functionality of a domain name is to provide recognizable names, to mostly numerically addressed Internet resources. This abstraction allows any website to be moved to a different physical location in the address topology of the network, in effect changing the IP address. This translation from domain names to IP addresses is accomplished with the global facilities of Domain Name System (DNS). By allowing the use of unique alphabetical addresses instead of numeric ones, domain names allow webt users to more easily find web sites and any other IP-based communications services. The flexibility of the domain name system allows multiple IP addresses to be assigned to a single domain name, or multiple domain names to be services from a single IP address. This means that one server may have multiple roles (such as hosting multiple independent websites), or that one role can be spread among many servers. One IP address can also be assigned to several servers, as used in anycast networking.
Wednesday, June 3, 2009
Domain Name Defined
By definition, domain names are restricted to the ASCII letters A-Z, the digits 0-9, and the hyphen, with some other restrictions in terms of name length and position of hyphens. Since this does not allow the use of many characters found in non-English languages, and no multi-byte characters necessary for most Asian languages, the Internationalized domain name (IDN) system has been developed and is now in testing stage with a set of top-level domains established for this purpose.
The underscore character is frequently used to ensure that a domain name is not recognized as a hostname, as with the use of SRV records, for example, although some older systems such as NetBIOS did allow it. To avoid confusion and for other reasons, domain names with underscores in them are sometimes used where hostnames are required.
Domain names are often referred to simply as domains and domain name registrants are referred to as domain owners, although domain name registration with a registrar does not confer any legal ownership of the name, only an exclusive right of use.
The underscore character is frequently used to ensure that a domain name is not recognized as a hostname, as with the use of SRV records, for example, although some older systems such as NetBIOS did allow it. To avoid confusion and for other reasons, domain names with underscores in them are sometimes used where hostnames are required.
Domain names are often referred to simply as domains and domain name registrants are referred to as domain owners, although domain name registration with a registrar does not confer any legal ownership of the name, only an exclusive right of use.
Tuesday, June 2, 2009
Domain Name Examples
The following example illustrates the difference between a URL (Uniform Resource Locator) and a domain name:
URL: http://www.antivira.com/index.html
Domain name: www.antivira.com
Registered domain name: antivira.com
As a rule, the IP address and the server name are interchangeable. For most Internet services, the server will not have any way to know which was used. However, the explosion of interest in the Web means that there are far more Web sites than servers. To accommodate this, the hypertext transfer protocol (HTTP) specifies that the client tells the server which name is being used. This way, one server with one IP address can provide different sites for different domain names. This feature goes under the name virtual hosting and is commonly used by Web hosts.
For example, as referenced in RFC 2606 (Reserved Top Level DNS Names), the server at IP address 208.77.188.166 handles all of the following sites:
example.com
www.example.com
example.net
www.example.net
example.org
www.example.org
When a request is made, the data corresponding to the hostname requested is provided to the user.
URL: http://www.antivira.com/index.html
Domain name: www.antivira.com
Registered domain name: antivira.com
As a rule, the IP address and the server name are interchangeable. For most Internet services, the server will not have any way to know which was used. However, the explosion of interest in the Web means that there are far more Web sites than servers. To accommodate this, the hypertext transfer protocol (HTTP) specifies that the client tells the server which name is being used. This way, one server with one IP address can provide different sites for different domain names. This feature goes under the name virtual hosting and is commonly used by Web hosts.
For example, as referenced in RFC 2606 (Reserved Top Level DNS Names), the server at IP address 208.77.188.166 handles all of the following sites:
example.com
www.example.com
example.net
www.example.net
example.org
www.example.org
When a request is made, the data corresponding to the hostname requested is provided to the user.
Saturday, May 30, 2009
Top-level domains
Top-level domains
Every domain name ends in a top-level domain (TLD) name, which is either one of a small list of generic names (three or more characters), or a two-character territory code based on ISO-3166 (there are few exceptions and new codes are integrated case by case). Top-level domains are also called first-level domains.
The generic top-level domain (gTLD) extensions are:
CURRENT
Generic: .biz · .com · .info · .name · .net · .org · .pro
Sponsored: .aero · .asia · .cat · .coop · .edu · .gov · .int · .jobs · .mil · .mobi · .museum · .tel · .travel
Infrastructure: .arpa
Deleted/retired: .nato
Reserved: .example · .invalid · .localhost · .test
Pseudo: .bitnet · .csnet · .local · .root · .uucp · .onion · .exit
PROPOSED
Locations: .berlin · .lat · .nyc
Language and nationality: .bzh · .cym · .gal · .lli · .scot
Technical: .geo · .mail
Other: .kids · .post · .shop · .web · .xxx
Every domain name ends in a top-level domain (TLD) name, which is either one of a small list of generic names (three or more characters), or a two-character territory code based on ISO-3166 (there are few exceptions and new codes are integrated case by case). Top-level domains are also called first-level domains.
The generic top-level domain (gTLD) extensions are:
CURRENT
Generic: .biz · .com · .info · .name · .net · .org · .pro
Sponsored: .aero · .asia · .cat · .coop · .edu · .gov · .int · .jobs · .mil · .mobi · .museum · .tel · .travel
Infrastructure: .arpa
Deleted/retired: .nato
Reserved: .example · .invalid · .localhost · .test
Pseudo: .bitnet · .csnet · .local · .root · .uucp · .onion · .exit
PROPOSED
Locations: .berlin · .lat · .nyc
Language and nationality: .bzh · .cym · .gal · .lli · .scot
Technical: .geo · .mail
Other: .kids · .post · .shop · .web · .xxx
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