Domain names, arranged in a tree, cut into zones, each served by a nameserver.

The domain name space consists of a tree of domain names. Each node or leaf in the tree has one or more resource records, which hold information associated with the domain name. The tree sub-divides into zones. A zone consists of a collection of connected nodes authoritatively served by an authoritative DNS nameserver. (Note that a single nameserver can host several zones.)

When a system administrator wants to let another administrator control a part of the domain name space within his or her zone of authority, he or she can delegate control to the other administrator. This splits a part of the old zone off into a new zone, which comes under the authority of the second administrator's nameservers. The old zone becomes no longer authoritative for what goes under the authority of the new zone.

A resolver looks up the information associated with nodes. A resolver knows how to communicate with name servers by sending DNS requests, and heeding DNS responses. Resolving usually entails iterating through several name servers to find the needed information.

Some resolvers function simplistically and can only communicate with a single name server. These simple resolvers rely on a recursing name server to perform the work of finding information for them.

Parts of a domain name

A domain name usually consists of two or more parts (technically labels), separated by dots. For example wikipedia.org.

• The rightmost label conveys the top-level domain (for example, the address en.wikipedia.org has the top-level domain org).
• Each label to the left specifies a subdivision or subdomain of the domain above it. Note that "subdomain" expresses relative dependence, not absolute dependence: for example, wikipedia.org comprises a subdomain of the org domain, and en.wikipedia.org comprises a subdomain of the domain wikipedia.org. In theory, this subdivision can go down to 127 levels deep, and each label can contain up to 63 characters, as long as the whole domain name does not exceed a total length of 255 characters. But in practice some domain registries have shorter limits than that.
• A hostname refers to a domain name that has one or more associated IP addresses. For example, the en.wikipedia.org and wikipedia.org domains are both hostnames, but the org domain is not.

The Domain Name System consists of a hierarchical set of DNS servers. Each domain or subdomain has one or more authoritative DNS servers that publish information about that domain and the name servers of any domains "beneath" it. The hierarchy of authoritative DNS servers matches the hierarchy of domains. At the top of the hierarchy stand the root nameservers: the servers to query when looking up (resolving) a top-level domain name (TLD).

Iterative and recursive queries:

• An Iterative query is one where the DNS server may provide a partial answer to the query (or give an error). DNS servers must support non-recursive queries.
• A recursive query is one where the DNS server will fully answer the query (or give an error). DNS servers are not required to support recursive queries and both the resolver (or another DNS acting recursively on behalf of another resolver) negotiate use of recursive service using bits in the query headers.

Address resolution mechanism

(This description deliberately uses the fictional .example TLD in accordance with the DNS guidelines themselves.)

In theory a full host name may have several name segments, (e.g ahost.ofasubnet.ofabiggernet.inadomain.example). In practice, in the experience of the majority of public users of Internet services, full host names will frequently consist of just three segments (ahost.inadomain.example, and most often www.inadomain.example).

For querying purposes, software interprets the name segment by segment, from right to left, using an iterative search procedure. At each step along the way, the program queries a corresponding DNS server to provide a pointer to the next server which it should consult.

A DNS recursor consults three nameservers to resolve the address www.wikipedia.org.

As originally envisaged, the process was as simple as:

1. the local system is pre-configured with the known addresses of the root servers in a file of root hints, which need to be updated periodically by the local administrator from a reliable source to be kept up to date with the changes which occur over time.
2. query one of the root servers to find the server authoritative for the next level down (so in the case of our simple hostname, a root server would be asked for the address of a server with detailed knowledge of the example top level domain).
3. querying this second server for the address of a DNS server with detailed knowledge of the second-level domain (inadomain.example in our example).
4. repeating the previous step to progress down the name, until the final step which would, rather than generating the address of the next DNS server, return the final address sought.

The diagram illustrates this process for the real host www.wikipedia.org.

The mechanism in this simple form has a difficulty: it places a huge operating burden on the root servers, with each and every search for an address starting by querying one of them. Being as critical as they are to the overall function of the system such heavy use would create an insurmountable bottleneck for trillions of queries placed every day.

Circular dependencies and glue records

Name servers in delegations appear listed by name, rather than by IP address. This means that a resolving name server must issue another DNS request to find out the IP address of the server to which it has been referred. Since this can introduce a circular dependency if the nameserver referred to is under the domain that it is authoritative of, it is occasionally necessary for the nameserver providing the delegation to also provide the IP address of the next nameserver. This record is called a glue record.

For example, assume that the sub-domain en.wikipedia.org contains further sub-domains (such as something.en.wikipedia.org) and that the authoritative nameserver for these lives at ns1.en.wikipedia.org. A computer trying to resolve something.en.wikipedia.org will thus first have to resolve ns1.en.wikipedia.org. Since ns1 is also under the en.wikipedia.org subdomain, resolving ns1.en.wikipedia.org requires resolving ns1.en.wikipedia.org which is exactly the circular dependency mentioned above. The dependency is broken by the glue record in the nameserver of wikipedia.org that provides the IP address of ns1.en.wikipedia.org directly to the requestor, enabling it to bootstrap the process by figuring out where ns1.en.wikipedia.org is located.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

When an application (such as a web browser) tries to find the IP address of a domain name, it doesn't necessarily follow all of the steps outlined in the Theory section above. We will first look at the concept of caching, and then outline the operation of DNS in "the real world."

Caching and time to live

Because of the huge volume of requests generated by a system like DNS, the designers wished to provide a mechanism to reduce the load on individual DNS servers. To this end, the DNS resolution process allows for caching (i.e. the local recording and subsequent consultation of the results of a DNS query) for a given period of time after a successful answer. How long a resolver caches a DNS response (i.e. how long a DNS response remains valid) is determined by a value called the time to live (TTL). The TTL is set by the administrator of the DNS server handing out the response. The period of validity may vary from just seconds to days or even weeks.

Caching time

As a noteworthy consequence of this distributed and caching architecture, changes to DNS do not always take effect immediately and globally. This is best explained with an example: If an administrator has set a TTL of 6 hours for the host www.wikipedia.org, and then changes the IP address to which www.wikipedia.org resolves at 12:01pm, the administrator must consider that a person who cached a response with the old IP address at 12:00pm will not consult the DNS server again until 6:00pm. The period between 12:01pm and 6:00pm in this example is called caching time, which is best defined as a period of time that begins when you make a change to a DNS record and ends after the maximum amount of time specified by the TTL expires. This essentially leads to an important logistical consideration when making changes to DNS: not everyone is necessarily seeing the same thing you're seeing. RFC 1537 helps to convey basic rules for how to set the TTL.

Note that the term "propagation", although very widely used in this context, does not describe the effects of caching well. Specifically, it implies that [1] when you make a DNS change, it somehow spreads to all other DNS servers (instead, other DNS servers check in with yours as needed), and [2] that you do not have control over the amount of time the record is cached (you control the TTL values for all DNS records in your domain, except your NS records and any authoritative DNS servers that use your domain name).

Some resolvers may override TTL values, as the protocol supports caching for up to 68 years or no caching at all. Negative caching (the non-existence of records) is determined by name servers authoritative for a zone which MUST include the SOA record when reporting no data of the requested type exists. The MINIMUM field of the SOA record and the TTL of the SOA itself is used to establish the TTL for the negative answer. RFC 2308

Many people incorrectly refer to a mysterious 48 hour or 72 hour propagation time when you make a DNS change. When one changes the NS records for one's domain or the IP addresses for hostnames of authoritative DNS servers using one's domain (if any), there can be a lengthy period of time before all DNS servers use the new information. This is because those records are handled by the zone parent DNS servers (for example, the .com DNS servers if your domain is example.com), which typically cache those records for 48 hours. However, those DNS changes will be immediately available for any DNS servers that do not have them cached. And any DNS changes on your domain other than the NS records and authoritative DNS server names can be nearly instantaneous, if you choose for them to be (by lowering the TTL once or twice ahead of time, and waiting until the old TTL expires before making the change).

In the real world

DNS resolving from program to OS-resolver to ISP-resolver to greater system.

Users generally do not communicate directly with a DNS resolver. Instead DNS resolution takes place transparently in client applications such as web browsers, mail clients, and other Internet applications. When a request is made which necessitates a DNS lookup, such programs send a resolution request to the local DNS resolver in the operating system which in turn handles the communications required.

The DNS resolver will almost invariably have a cache (see above) containing recent lookups. If the cache can provide the answer to the request, the resolver will return the value in the cache to the program that made the request. If the cache does not contain the answer, the resolver will send the request to a designated DNS server or servers. In the case of most home users, the Internet service provider to which the machine connects will usually supply this DNS server: such a user will either have configured that server's address manually or allowed DHCP to set it; however, where systems administrators have configured systems to use their own DNS servers, their DNS resolvers point to separately maintained nameservers of the organization. In any event, the name server thus queried will follow the process outlined above, until it either successfully finds a result or does not. It then returns its results to the DNS resolver; assuming it has found a result, the resolver duly caches that result for future use, and hands the result back to the software which initiated the request.

Broken resolvers

An additional level of complexity emerges when resolvers violate the rules of the DNS protocol. Some people have suggested that a number of large ISPs have configured their DNS servers to violate rules (presumably to allow them to run on less-expensive hardware than a fully compliant resolver), such as by disobeying TTLs, or by indicating that a domain name does not exist just because one of its name servers does not respond.

As a final level of complexity, some applications such as Web browsers also have their own DNS cache, in order to reduce the use of the DNS resolver library itself. This practice can add extra difficulty to DNS debugging, as it obscures which data is fresh, or lies in which cache. These caches typically have very short caching times of the order of one minute. A notable exception is Internet Explorer; recent versions cache DNS records for half an hour.

Other applications

The system outlined above provides a somewhat simplified scenario. The Domain Name System includes several other functions:

• Hostnames and IP addresses do not necessarily match on a one-to-one basis. Many hostnames may correspond to a single IP address: combined with virtual hosting, this allows a single machine to serve many web sites. Alternatively a single hostname may correspond to many IP addresses: this can facilitate fault tolerance and load distribution, and also allows a site to move physical location seamlessly.
• There are many uses of DNS besides translating names to IP addresses. For instance, Mail transfer agents use DNS to find out where to deliver e-mail for a particular address. The domain to mail exchanger mapping provided by MX records accommodates another layer of fault tolerance and load distribution on top of the name to IP address mapping.
• Sender Policy Framework and DomainKeys instead of creating their own record types were designed to take advantage of another DNS record type, the TXT record.
• To provide resilience in the event of computer failure, multiple DNS servers are usually provided for coverage of each domain, and at the top level, thirteen very powerful root servers exist, with additional "copies" of several of them distributed worldwide via Anycast.

DNS primarily uses UDP on port 53 [2] to serve requests. Almost all DNS queries consist of a single UDP request from the client followed by a single UDP reply from the server. TCP comes into play only when the response data size exceeds 512 bytes, or for such tasks as zone transfer. Some operating systems such as HP-UX are known to have resolver implementations that use TCP for all queries, even when UDP would suffice.

Extensions to DNS

EDNS is an extension of the DNS protocol which enhances the transport of DNS data in UDP packages, and adds support for expanding the space of request and response codes. It is described in RFC 2671.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

• RFC 882 Concepts and Facilities (Deprecated by RFC 1034)
• RFC 883 Domain Names: Implementation specification (Deprecated by RFC 1035)
• RFC 920 Specified original TLDs: .arpa, .com, .edu, .org, .gov, .mil and two-character country codes
• RFC 1032 Domain administrators guide
• RFC 1033 Domain administrators operations guide
• RFC 1034 Domain Names - Concepts and Facilities.
• RFC 1035 Domain Names - Implementation and Specification
• RFC 1101 DNS Encodings of Network Names and Other Types
• RFC 1123 Requirements for Internet Hosts -- Application and Support
• RFC 1183 New DNS RR Definitions
• RFC 1706 DNS NSAP Resource Records
• RFC 1876 Location Information in the DNS (LOC)
• RFC 1886 DNS Extensions to support IP version 6
• RFC 1912 Common DNS Operational and Configuration Errors
• RFC 1995 Incremental Zone Transfer in DNS
• RFC 1996 A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)
• RFC 2136 Dynamic Updates in the domain name system (DNS UPDATE)
• RFC 2181 Clarifications to the DNS Specification
• RFC 2182 Selection and Operation of Secondary DNS Servers
• RFC 2308 Negative Caching of DNS Queries (DNS NCACHE)
• RFC 2317 Classless IN-ADDR.ARPA delegation
• RFC 2671 Extension Mechanisms for DNS (EDNS0)
• RFC 2672 Non-Terminal DNS Name Redirection (DNAME record)
• RFC 2782 A DNS RR for specifying the location of services (DNS SRV)
• RFC 2845 Secret Key Transaction Authentication for DNS (TSIG)
• RFC 2874 DNS Extensions to Support IPv6 Address Aggregation and Renumbering
• RFC 3403 Dynamic Delegation Discovery System (DDDS) (NAPTR records)
• RFC 3696 Application Techniques for Checking and Transformation of Names
• RFC 4398 Storing Certificates in the Domain Name System
• RFC 4408 Sender Policy Framework (SPF) (SPF records)

Important categories of data stored in DNS include the following:

• An A record or address record maps a hostname to a 32-bit IPv4 address.
• An AAAA record or IPv6 address record maps a hostname to a 128-bit IPv6 address.
• A CNAME record or canonical name record is an alias of one name to another. The A record to which the alias points can be either local or remote - on a foreign name server. This is useful when running multiple services (like an FTP and a webserver) from a single IP address. Each service can then have its own entry in DNS (like ftp.example.com. and www.example.com.)
• An MX record or mail exchange record maps a domain name to a list of mail exchange servers for that domain.
• A PTR record or pointer record maps an IPv4 address to the canonical name for that host. Setting up a PTR record for a hostname in the in-addr.arpa. domain that corresponds to an IP address implements reverse DNS lookup for that address. For example (at the time of writing), www.icann.net has the IP address 192.0.34.164, but a PTR record maps 164.34.0.192.in-addr.arpa to its canonical name, referrals.icann.org.
• An NS record or name server record maps a domain name to a list of DNS servers authoritative for that domain. Delegations depend on NS records.
• An SOA record or start of authority record specifies the DNS server providing authoritative information about an Internet domain, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.
• An SRV record is a generalized service location record.
• A TXT record allows an administrator to insert arbitrary text into a DNS record. For example, this record is used to implement the Sender Policy Framework and DomainKeys specifications.
• NAPTR records ("Naming Authority Pointer") are a newer type of DNS record that support regular expression based rewriting.

Other types of records simply provide information (for example, a LOC record gives the physical location of a host), or experimental data (for example, a WKS record gives a list of servers offering some well known service such as HTTP or POP3 for a domain).

When sent over the internet, all records use the common format specified in RFC 1035 shown below.

For a complete list of DNS Record types consult IANA DNS Parameters.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Internationalized domain names

While domain names technically have no restrictions on the characters they use and can include non-ASCII characters, the same is not true for host names. Host names are the names most people see and use for things like e-mail and web browsing. Host names are restricted to a small subset of the ASCII character set that includes the Roman alphabet in upper and lower case, the digits 0 through 9, the dot, and the hyphen. (See RFC 3696 section 2 for details.) This prevented the representation of names and words of many languages natively. ICANN has approved the Punycode-based IDNA system, which maps Unicode strings into the valid DNS character set, as a workaround to this issue. Some registries have adopted IDNA.

Security issues

DNS was not originally designed with security in mind, and thus has a number of security issues. DNS responses are traditionally not cryptographically signed, leading to many attack possibilities; DNSSEC modifies DNS to add support for cryptographically signed responses. There are various extensions to support securing zone transfer information as well.

Even with encryption it still doesn't prevent the possibility that a DNS server could become infected with a virus (or for that matter a disgruntled employee) that would cause IP addresses of that server to be redirected to a malicious address with a long TTL. This could have far reaching impact to potentially millions of internet users if busy DNS servers cache the bad IP data. This would require manual purging of all affected DNS caches as required by the long TTL (up to 68 years).

Some domain names can spoof other, similar-looking domain names. For example, "paypal.com" and "paypa1.com" are different names, yet users may be unable to tell the difference when the user's typeface (font) does not clearly differentiate the letter l and the number 1. This problem is much more serious in systems that support internationalized domain names, since many characters that are different, from the point of view of ISO 10646, appear identical on typical computer screens.

Legal users of domains

Registrant

Most of the NICs in the world receive an annual fee from a legal user in order for the legal user to utilize the domain name (i.e. a sort of a leasing agreement exists, subject to the registry's terms and conditions). Depending on the various naming convention of the registries, legal users become commonly known as "registrants" or as "domain holders".

ICANN holds a complete list of domain registries in the world. One can find the legal user of a domain name by looking in the WHOIS database held by most domain registries.

For most of the more than 240 country code top-level domains (ccTLDs), the domain registries hold the authoritative WHOIS (Registrant, name servers, expiry dates, etc.). For instance, DENIC, Germany NIC, holds the authoritative WHOIS to a .DE domain name.

However, some domain registries, such as for .COM, .ORG, .INFO, etc., use a registry-registrar model. There are hundreds of Domain Name Registrars that actually perform the domain name registration with the end user (see lists at ICANN or VeriSign). By using this method of distribution, the registry only has to manage the relationship with the registrar, and the registrar maintains the relationship with the end users, or 'registrants'. For .COM, .NET domain names, the domain registries, VeriSign holds a basic WHOIS (registrar and name servers, etc.). One can find the detailed WHOIS (registrant, name servers, expiry dates, etc.) at the registrars.

Since about 2001, most gTLD registries (.ORG, .BIZ, .INFO) have adopted a so-called "thick" registry approach, i.e. keeping the authoritative WHOIS with the various registries instead of the registrars.

Administrative contact

A registrant usually designates an administrative contact to manage the domain name. In practice, the administrative contact usually has the most immediate power over a domain. Management functions delegated to the administrative contacts may include (for example):

• the obligation to conform to the requirements of the domain registry in order to retain the right to use a domain name
• authorization to update the physical address, e-mail address and telephone number etc. in WHOIS

Technical contact

A technical contact manages the name servers of a domain name. The many functions of a technical contact include:

• making sure the configurations of the domain name conforms to the requirements of the domain registry
• updating the domain zone
• providing the 24×7 functionality of the name servers (that leads to the accessibility of the domain name)

Billing contact

The party whom a NIC invoices.

Name servers

Namely the authoritative name servers that host the domain name zone of a domain name.

Politics

Many investigators have voiced criticism of the methods currently used to control ownership of domains. Critics commonly claim abuse by monopolies or near-monopolies, such as VeriSign, Inc. Particularly noteworthy was the VeriSign Site Finder system which redirected all unregistered .com and .net domains to a VeriSign webpage. Despite widespread criticism, VeriSign only reluctantly removed it after the Internet Corporation for Assigned Names and Numbers (ICANN) threatened to revoke its contract to administer the root name servers.

There is also significant disquiet regarding the United States' political influence over ICANN. This was a significant issue in the attempt to create a .xxx top-level domain and sparked greater interest in alternative DNS roots that would be beyond the control of any single country.

Truth in Domain Names Act

In the United States, the "Truth in Domain Names Act" (actually the "Anticybersquatting Consumer Protection Act"), in combination with the PROTECT Act, forbids the use of a misleading domain name with the intention of attracting people into viewing a visual depiction of sexually explicit conduct on the Internet.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

The term domain name has multiple related meanings:

• A name that identifies a computer or computers on the internet. These names appear as a component of a Web site's URL, e.g. wikipedia.org. This type of domain name is also called a hostname.
• The product that domain name registrars provide to their customers. These names are often called registered domain names.
• Names used for other purposes in the Domain Name System (DNS), for example the special name which follows the @ sign in an email address, or the Top-level domains like .com, or the names used by the Session Initiation Protocol (VoIP), or DomainKeys.

They are sometimes colloquially (and incorrectly) referred to by marketers as "web addresses".

Overview

The most common types of domain names are hostnames that provide more memorable names to stand in for numeric IP addresses. They allow for any service to move to a different location in the topology of the Internet (or an intranet), which would then have a different IP address.

By allowing the use of unique alphabetical addresses instead of numeric ones, domain names allow Internet users to more easily find and communicate with web sites and other server-based 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 assigned to a single IP address. This means that one server may have multiple roles (such as hosting multiple independent Web sites), or that one role can be spread among many servers. One IP address can also be assigned to several servers, as used in anycast and hijacked IP space.

Hostnames are restricted to the ASCII letters "a" through "z" (case-insensitive), the digits "0" through "9", and the hyphen, with some other restrictions. Registrars restrict the domains to valid hostnames, since, otherwise, they would be useless. The Internationalized domain name (IDN) system has been developed to bypass the restrictions on character allowances in hostnames, making it easier for users of non-english alphabets to use the Internet. The underscore character is frequently used to ensure that a domain name is not recognized as a hostname, for example with the use of SRV records, although some older systems, such as NetBIOS did allow it. Due to confusion and other reasons, domain names with underscores in them are sometimes used where hostnames are required.

Examples

The following example illustrates the difference between a URL (Uniform Resource Locator) and a domain name:

URL: http://www.example.net/index.html

Domain name: www.example.net

Registered domain name: example.net

As a general 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 192.0.34.166 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 served to the user.

Top-level domains

Every domain name ends in a top-level domain (TLD) name, which is always 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 sometimes also called first-level domains.

The generic top-level domain (gTLD) extensions are:

Generic top-level domains

• Unsponsored  .biz  .com  .edu  .gov  .info  .int  .mil  .name  .net  .org
• Sponsored  .aero  .asia  .cat  .coop  .jobs  .mobi  .museum  .pro  .tel  .travel
• Infrastructure  .arpa  .root
• Proposed  .berlin  .bzh  .cym  .gal  .geo  .kid  .kids  .lat  .mail  .nyc  .post  .sco  .web  .xxx
• Deleted/retired  .nato
• Reserved  .example  .invalid  .localhost  .test
• Pseudo-domains  .bitnet  .csnet  .ip  .local  .onion  .uucp
• Unofficial  

The country code top-level domain (ccTLD) extensions are:

Country code top-level domains

Active:  .ac  .ad  .ae  .af  .ag  .ai  .al  .am  .an  .ao  .aq  .ar  .as  .at  .au  .aw  .ax  .az  .ba  .bb  .bd  .be  .bf  .bg  .bh  .bi  .bj  .bm  .bn  .bo  .br  .bs  .bt  .bw  .by  .bz  .ca  .cc  .cd  .cf  .cg  .ch  .ci  .ck  .cl  .cm  .cn  .co  .cr  .cu  .cv  .cx  .cy  .cz  .de  .dj  .dk  .dm  .do  .dz  .ec  .ee  .eg  .er  .es  .et  .eu  .fi  .fj  .fk  .fm  .fo  .fr  .ga  .gd  .ge  .gf  .gg  .gh  .gi  .gl  .gm  .gn  .gp  .gq  .gr  .gs  .gt  .gu  .gw  .gy  .hk  .hm  .hn  .hr  .ht  .hu  .id  .ie  .il  .im  .in  .io  .iq  .ir  .is  .it  .je  .jm  .jo  .jp  .ke  .kg  .kh  .ki  .km  .kn  .kr  .kw  .ky  .kz  .la  .lb  .lc  .li  .lk  .lr  .ls  .lt  .lu  .lv  .ly  .ma  .mc  .md  .mg  .mh  .mk  .ml  .mm  .mn  .mo  .mp  .mq  .mr  .ms  .mt  .mu  .mv  .mw  .mx  .my  .mz  .na  .nc  .ne  .nf  .ng  .ni  .nl  .no  .np  .nr  .nu  .nz  .om  .pa  .pe  .pf  .pg  .ph  .pk  .pl  .pn  .pr  .ps  .pt  .pw  .py  .qa  .re  .ro  .ru  .rw  .sa  .sb  .sc  .sd  .se  .sg  .sh  .si  .sk  .sl  .sm  .sn  .sr  .st  .sv  .sy  .sz  .tc  .td  .tf  .tg  .th  .tj  .tk  .tl  .tm  .tn  .to  .tr  .tt  .tv  .tw  .tz  .ua  .ug  .uk  .us  .uy  .uz  .va  .vc  .ve  .vg  .vi  .vn  .vu  .wf  .ws  .ye  .yu  .za  .zm  .zw

Reserved/unassigned:  .eh  .kp  .me  .rs  .um       Allocated/unused:  .bv  .gb  .pm  .sj  .so  .yt       Phaseout:  .su  .tp       Deleted/retired:  .bu  .cs  .dd  .zr

Other-level domains

In addition to the top-level domains, there are second-level domain (SLD) names. These are the names directly to the left of .com, .net, and the other top-level domains. As an example, in the domain en.wikipedia.org, "wikipedia" is the second-level domain.

On the next level are third-level domains. These domains are immediately to the left of a second-level domain. In the en.wikipedia.org example, "en" is a third-level domain. There can be fourth and fifth level domains and so on, with virtually no limitation. An example of a working domain with five levels is www.sos.state.oh.us. Each level is separated by a dot or period symbol between them.

Domains of third or higher level are also known as subdomains, though this term technically applies to a domain of any level, since even a top-level domain is a "subdomain" of the "root" domain (a "zeroth-level" domain that is designated by a dot alone).

Traditionally, the second level domain was the name of the company or the name used on the internet. The third level was commonly used to designate a particular host server. Therefore, ftp.wikipedia.org might be an FTP server, www.wikipedia.org would be a World Wide Web Server, and mail.wikipedia.org could be an email server. Modern technology now allows multiple servers to serve a single subdomain, or multiple protocols or domains to be served by a single computer. Therefore, subdomains may or may not have any real purpose.

Official assignment

ICANN (Internet Corporation for Assigned Names and Numbers) has overall responsibility for managing the DNS. It controls the root domain, delegating control over each top-level domain to a domain name registry. For ccTLDs, the domain registry is typically controlled by the government of that country. ICANN has a consultation role in these domain registries but is in no position to regulate the terms and conditions of how a domain name is allocated or who allocates it in each of these country level domain registries. On the other hand, generic top-level domains (gTLDs) are governed directly under ICANN which means all terms and conditions are defined by ICANN with the cooperation of the gTLD registries.

Domain names which are theoretically leased can be considered in the same way as real estate, due to a significant impact on online brand building, advertising, search engine optimization, etc.

A few companies have offered low-cost, below-cost or even free domain registrations, with a variety of models adopted to recoup the costs to the provider. These usually require that domains are hosted on their site in a framework or portal, with advertising wrapped around the user's content, revenue from which allows the provider to recoup the costs. When the DNS was new, domain registrations were free. A domain owner can generally give away or sell infinite subdomains of their domain, e.g. the owner of example.edu could provide domains that are subdomains, such as foo.example.edu and foo.bar.example.edu.

Uses and abuses

As domain names became attractive to marketers, rather than just the technical audience for which they were originally intended, they began to be used in manners that in many cases did not fit in their intended structure. As originally planned, the structure of domain names followed a strict hierarchy in which the top level domain indicated the type of organization (commercial, governmental, etc.), and addresses would be nested down to third, fourth, or further levels to express complex structures, where, for instance, branches, departments, and subsidiaries of a parent organization would have addresses which were subdomains of the parent domain. Also, hostnames were intended to correspond to actual physical machines on the network, generally with only one name per machine.

However, once the World Wide Web became popular, site operators frequently wished to have memorable addresses, regardless of whether they fit properly in the structure; thus, since the .com domain was the most popular and memorable, even noncommercial sites would often get addresses under it, and sites of all sorts wished to have second-level domain registrations even if they were parts of a larger entity where a logical subdomain would have made sense (e.g., abcnews.com instead of news.abc.com). A Web site found at http://www.example.org/ will often be advertised without the "http://", and in most cases can be reached by just entering "example.org" into a Web browser. In the case of a .com, the Web site can sometimes be reached by just entering "example" (depending on browser versions and configuration settings, which vary in how they interpret incomplete addresses).

The popularity of domain names also led to uses which were regarded as abusive by established companies with trademark rights; this was known as cybersquatting, in which somebody took a name that resembled a trademark in order to profit from traffic to that address. To combat this, various laws and policies were enacted to allow abusive registrations to be forcibly transferred, but these were sometimes themselves abused by overzealous companies committing reverse domain hijacking against domain users who had legitimate grounds to hold their names, such as their being generic words as well as trademarks in a particular context, or their use in the context of fan or protest sites with free speech rights of their own.

Laws that specifically address domain name conflicts include the Anticybersquatting Consumer Protection Act in the United States and the Trademarks Act, 1999, in India. Alternatively, domain registrants are bound by contract under the UDRP to comply with mandatory arbitration proceedings should someone challenge their ownership of the domain name.

Generic domain names — problems arising out of unregulated name selection

Within a particular top-level domain, parties are generally free to select an unallocated domain name as their own on a first come, first served basis, resulting in Harris's lament, all the good ones are taken. For generic or commonly used names, this may sometimes lead to the use of a domain name which is inaccurate or misleading. This problem can be seen with regard to the ownership or control of domain names for a generic product or service.

By way of illustration, there has been tremendous growth in the number and size of literary festivals around the world in recent years. In this context, currently a generic domain name such as literary.org is available to the first literary festival organisation which is able to obtain registration, even if the festival in question is very young or obscure. Some critics would argue that there is greater amenity in reserving such domain names for the use of, for example, a regional or umbrella grouping of festivals. Related issues may also arise in relation to non-commercial domain names.

Unconventional domain names

Due to the rarity of one-word dot-com domain names, many unconventional domain names, domain hacks, have been gaining popularity. They make use of the top-level domain as an integral part of the Web site's title. Two popular domain hack Web sites are del.icio.us and blo.gs, which spell out "delicious" and "blogs", respectively.

Unconventional domain names are also used to create unconventional email addresses. Non-working examples that spell 'James' are j@m.es and j@mes.com, which use the domain names m.es (of Spain's .es) and mes.com, respectively.

Domain name confusion

Intercapping is often used to clarify a domain name. However, DNS is case-insensitive, and some names may be misinterpreted when converted to lowercase. For example: Who Represents, a database of artists and agents, chose whorepresents.com; a therapists' network thought therapistfinder.com looked good; and another website operating as of October 2006, is penisland.net a website for Pen Island, a site that claims to be an online pen vendor, but exists primarily as a joke, as it has no products for sale. Other examples include cummingfirst.com, website of the Cumming First United Church in Cumming, GA and powergenitalia.com, a website for an Italian Power Generator company. In such situations, the proper wording can be clarified by use of hyphens. For instance, Experts Exchange, the programmers' site, for a long time used expertsexchange.com, but ultimately changed the name to experts-exchange.com.

Leo Stoller threatened to sue the owners of StealThisEmail.com on the basis that, when read as stealthisemail.com, it infringed on claimed trademark rights to the word "stealth". [5].

References

1. ^ [Steven] (2006-10-16). Sticking to The Business (HTML). Newsweek. The Washington Post Company.

Links

• RFC 1034, Domain Names—Concepts and Facilities, an Internet Protocol Standard.
• ICANN - Internet Corporation for Assigned Names and Numbers.
• UDRP, Uniform Domain-Name Dispute-Resolution Policy.
• Internic.net, public information regarding Internet domain name registration services.
• IANA generic TLD
• IANA Two letter Country Code TLD

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Registrant

Most of the NICs in the world receive an annual fee from a legal user in order for the legal user to utilize the domain name (i.e. a sort of a leasing agreement exists, subject to the registry's terms and conditions). Depending on the various naming convention of the registries, legal users become commonly known as "registrants" or as "domain holders".

ICANN holds a complete list of domain registries in the world. One can find the legal user of a domain name by looking in the WHOIS database held by most domain registries.

For most of the more than 240 country code top-level domains (ccTLDs), the domain registries hold the authoritative WHOIS (Registrant, name servers, expiry dates, etc.). For instance, DENIC, Germany NIC, holds the authoritative WHOIS to a .DE domain name.

However, some domain registries, such as for .COM, .ORG, .INFO, etc., use a registry-registrar model. There are hundreds of Domain Name Registrars that actually perform the domain name registration with the end user (see lists at ICANN or VeriSign). By using this method of distribution, the registry only has to manage the relationship with the registrar, and the registrar maintains the relationship with the end users, or 'registrants'. For .COM, .NET domain names, the domain registries, VeriSign holds a basic WHOIS (registrar and name servers, etc.). One can find the detailed WHOIS (registrant, name servers, expiry dates, etc.) at the registrars.

Since about 2001, most gTLD registries (.ORG, .BIZ, .INFO) have adopted a so-called "thick" registry approach, i.e. keeping the authoritative WHOIS with the various registries instead of the registrars.

Administrative contact

A registrant usually designates an administrative contact to manage the domain name. In practice, the administrative contact usually has the most immediate power over a domain. Management functions delegated to the administrative contacts may include (for example):

• the obligation to conform to the requirements of the domain registry in order to retain the right to use a domain name
• authorization to update the physical address, e-mail address and telephone number etc. in WHOIS

Technical contact

A technical contact manages the name servers of a domain name. The many functions of a technical contact include:

• making sure the configurations of the domain name conforms to the requirements of the domain registry
• updating the domain zone
• providing the 24×7 functionality of the name servers (that leads to the accessibility of the domain name)

Billing contact

The party whom a NIC invoices.

Name servers

Namely the authoritative name servers that host the domain name zone of a domain name.

Politics

Many investigators have voiced criticism of the methods currently used to control ownership of domains. Critics commonly claim abuse by monopolies or near-monopolies, such as VeriSign, Inc. Particularly noteworthy was the VeriSign Site Finder system which redirected all unregistered .com and .net domains to a VeriSign webpage. Despite widespread criticism, VeriSign only reluctantly removed it after the Internet Corporation for Assigned Names and Numbers (ICANN) threatened to revoke its contract to administer the root name servers.

There is also significant disquiet regarding the United States' political influence over ICANN. This was a significant issue in the attempt to create a .xxx top-level domain and sparked greater interest in alternative DNS roots that would be beyond the control of any single country.

Truth in Domain Names Act

In the United States, the "Truth in Domain Names Act" (actually the "Anticybersquatting Consumer Protection Act"), in combination with the PROTECT Act, forbids the use of a misleading domain name with the intention of attracting people into viewing a visual depiction of sexually explicit conduct on the Internet.

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

A hostname (occasionally also, a sitename) is the unique name by which a network-attached device (which could consist of a computer, file server, network storage device, fax machine, copier, cable modem, etc.) is known on a network. The hostname is used to identify a particular host in various forms of electronic communication such as the World Wide Web, e-mail or Usenet.

On the Internet, the terms "hostname" and "domain name" are often used interchangeably, but there are subtle technical differences between them.

Overview

Hostnames are used by various naming systems, NIS, DNS, SMB, etc., and so the meaning of the word hostname will vary depending on naming system in question, which in turn varies by type of network. A hostname meaningful to a Microsoft NetBIOS workgroup may be an invalid Internet hostname. When presented with a hostname and no context, it is usually safe to assume that the network is the Internet and DNS is the hostname's naming system.

Host names are typically used in an administrative capacity and may appear in computer browser lists, active directory lists, IP address to hostname resolutions, email headers, etc. They are human-readable nick-names, which ultimately correspond to unique network hardware MAC addresses. In some cases the host name may contain embedded domain names and/or locations, non-dotted IP addresses, etc.

On a simple local area network, a hostname is usually a single word: for instance, an organization's CVS server might be named "cvs" or "server-1".

Internet hostnames

On the Internet, a hostname is a domain name assigned to the host. This is usually a combination of the host's local name with its parent domain's name. For example, "en.wikipedia.org" consists of a hostname ("en") and the domain name "wikipedia.org". This kind of hostname is translated into an IP address via the local hosts file, or the Domain Name System (DNS) resolver. It is possible for a single host to have several hostnames; but generally the operating system of the host prefers to have one hostname that the host uses for itself.

Any domain name can also be hostname, as long as the restrictions mentioned below are followed. So, for example, both "en.wikimedia.org" and "wikimedia.org" are hostnames because they both have IP addresses assigned to them. The domain name "pmtpa.wikimedia.org" is not a hostname since it does not have an IP address, but "rr.pmtpa.wikimedia.org" is a hostname. All hostnames are domain names, but not all domain names are hostnames.

Restrictions on valid host names

Hostnames, like all domain names, are made up of a series of "labels", with each label being separated by a dot. Each label must be between 1 and 63 characters long, and there is a maximum of 255 characters when all labels are combined.

Unlike domain names, hostname labels can only be made up of the ASCII letters 'a' through 'z' (case-insensitive), the digits '0' through '9', and the hyphen. Labels can not start nor end with a hyphen. Special characters other than the hyphen (and the dot between labels) are not allowed, although they are sometimes used anyway. Underscore characters are commonly used by Windows systems but according to RFC 952 they are not allowed and several systems, such as DomainKeys and the SRV record deliberately use the underscore to make sure their special domain names are not confused with a hostname. Since some systems will check to make sure that hostnames contain only valid characters and others do not, the use of the invalid characters such as the underscore has caused many subtle problems in systems that connect to the wider world.

So, the hostname "en.wikipedia.org" is made up of the DNS labels "en", "wikipedia" and "org". Labels such as "2600" and "3com" can be used in hostnames, but "-hi-" and "*hi*" are invalid.

A hostname is considered to be a fully qualified domain name (FQDN) if all the labels up to and including the top-level domain name (TLD) are specified. Depending on the system, an unqualified hostname such as "compsci" or "wikipedia" may be combined with default domain names in order to determine the fully qualified domain name. So, a student at Harvard may be able to send mail to "joe@compsci" and have it sent to compsci.harvard.edu.

Choosing host names

General guidelines on choosing a good hostnames are outlined in RFC 1178. The folklore interest of hostnames stems from the creativity and humour they often display. Interpreting a sitename is not unlike interpreting a vanity licence plate; one has to mentally unpack it, allowing for mono-case and length restrictions and the lack of whitespace. Hacker tradition deprecates dull, institutional-sounding names in favour of punchy, humorous, and clever coinages (except that it is considered appropriate for the official public gateway machine of an organisation to bear the organisation's name or acronym). Mythological references, cartoon characters, animal names, and allusions to sci-fi or fantasy literature are probably the most popular sources for sitenames (in roughly descending order). The obligatory comment is Harris's lament: "All the good ones are taken!"

It is often possible to guess a hostname for a particular institution. This is useful if you want to know if they operate network services like anonymous FTP, World-Wide Web or finger. First try the institution's name or obvious abbreviations thereof, with the appropriate domain appended, e.g. "mit.edu". If this fails, prepend "ftp." or "www." as appropriate, e.g. "www.data-io.com". You can use the ping command as a quick way to test whether a hostname is valid.

Notes and references

1. ^ Host name vs domain name explanation from the DNS OP IETF Working Group

Links

• RFC 952 - "DoD Internet host table specification."
• RFC 1034 - "DOMAIN NAMES - CONCEPTS AND FACILITIES" (In particular, section 3.5)
• RFC 1035 - "DOMAIN NAMES - IMPLEMENTATION AND SPECIFICATION" (In particular, section 2.3.1)
• RFC 1123 - "Requirements for Internet Hosts - Application and Support."
• RFC 1178 - "Choosing a Name for Your Computer"
• RFC 3696 - "Application Techniques for Checking and Transformation of Names"

• web-based tools working with hostnames at the Open Directory Project

This article was originally based on material from the Free On-line Dictionary of Computing, which is licensed under the GFDL.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

A domain name registry, also called Network Information Centre (NIC), is part of the Domain Name System (DNS) of the Internet which converts domain names to IP addresses. It is an organisation that manages the registration of Domain names within the top-level domains for which it is responsible, controls the policies of domain name allocation, and technically operates its top-level domain.

Domain names are managed under a hierarchy headed by the Internet Assigned Numbers Authority (IANA), which manages the top of the DNS tree by administrating the data in the root nameservers.

IANA also operates the .int registry for intergovernmental organisations, the .arpa zone for protocol administration purposes, and other critical zones such as root-servers.net.

IANA delegates all other domain name authority to other domain name registries such as VeriSign.

Country code top-level domains (ccTLD) are delegated by IANA to national registries such as DENIC in Germany, or Nominet in the United Kingdom.

Operation

Some name registries are government departments (e.g., the registry for the Vatican www.nic.va ). Some are co-operatives of internet service providers (such as DENIC) or not-for profit companies (such as Nominet UK). Others operate as commercial organizations, such as the US registry (www.nic.us).

The allocated and assigned domain names are made available by registries by use of the Whois system and via their Domain name servers.

Some registries sell the names directly (like SWITCH in Switzerland) and others rely solely on registrars to sell them.

Policies

Allocation policies

Generally, domain name registries operate a first-come-first-served system of allocation but may reject the allocation of specific domains on the basis of political, religious, historical, legal or cultural reasons.

For example, in the United States, between 1996 and 1998, InterNIC automatically rejected domain name applications based on a list of perceived obscenities.

Registries may also control matters of interest to their local communities: for example, the German, Japanese and Polish registries have introduced internationalized domain names to allow use of local non-ASCII characters.

Dispute policies

Domains which are registered with ICANN generally have to use the Uniform Domain-Name Dispute-Resolution Policy (UDRP), however, DENIC requires people to use the German civil courts, and Nominet UK deals with Intellectual Property and other disputes through its own dispute resolution service.

Cost of registration

The cost of domain registration is set by each individual registry.

Second-level domains

Domain name registries may also impose a system of second-level domains on users. DENIC, the registry for Germany (.de), does not impose second level domains. AFNIC, the registry for France (.fr), has some second level domains, but not all registrants have to use them, and Nominet UK, the registry for the United Kingdom (.uk), requires all names to have a second level domain.

Registrants of second-level domains sometimes act as a registry by offering sub-registrations to their registration. For example, registrations to .fami.ly are offered by the registrant of fami.ly and not by GPTC, the registry for Libya (.ly).

Links

• A list of links to domain name registration services around the world

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Domain name speculation refers to buying domains with the intent of selling them later for a higher price. The speculative element can be linked to news and current events, though the period during which such domains can be sold or flipped is limited. The main target of domain name speculation is generic words which can be valuable for type-in traffic and for the dominant position they would have in any field due to their descriptive nature. Hence generic words such as poker, insurance, travel, creditcards, sex and others are highly valuable targets of domain speculation in any Top Level Domain.

Sometimes, domain name speculation involves finding domain names early in a market (typically when a new domain is launched), registering them and waiting until the market grows to sell them. Domains such as business.com have sold for millions of US dollars.

The .com Top-Level Domain is the focus of most domain speculation activity as it is the largest TLD. There is domain speculation in other TLDs such as .net and to a lesser extent in .org. The gTLDs have also been the subject of much domain speculation and .info is perhaps the most active in this respect due to the low registration fees.

Domain name speculation also occurs in the ccTLDs such as .uk, .de and .us. The German .de has over 10 Million domains registered. The UK's .uk has over 5 Million domains registered, mainly in its commercial sub-domain .co.uk. The .de and .uk ccTLDs are mature markets where good domain names can command high prices. The .eu ccTLD is a good example of what happens when speculative activity overtakes ordinary domain registrations. A combination of an inept registry (Eurid) and excessive speculation by businesses exploiting a poorly structured regulatory framework meant that, according to EURid's own statistics, over 50% of the registrations could be considered to be at best speculative and at worst Domain name warehousing.

Specialist and repurposed ccTLDs have also seen elements of domain name speculation. One of the best examples is that of the .tv ccTLD which has found the fact that TV is an abbreviation for the word television to be rather lucrative. The .mobi TLD is a good example of a specialist TLD in that it is specifically targeted at mobile phones and similar mobile technology. The operators of .mobi, mTLD, have reserved some of the premium generic words which will be auctioned off. The intent is to create a more level playing field for those interesting in developing websites. The .mobi premium generic words and phrases list is a good example of the domain names that are at the heart of most early-market domain name speculation.

Domain name speculators also register domain names based on seemingly generic phrases such as propertyforsale in the hope that these domain names could be sold later to businesses. Typically, domain name speculators will try to stay away from domain names containing trademarks as this could be considered cybersquatting.

Primary market speculation

The primary market for domain name speculation covers newly registered domain names that have not been registered before. Such domain names are often linked to news and current events and have not been registered before. They are in reality new domain names. These would be domain name registrations in new TLDs.

Secondary market speculation

The secondary market for domain names covers previously registered domain names that have not been renewed by their registrants. Sometimes these dropped domain names can be more valuable due to their having had high-profile websites associated with them. Others can be valuable because of the generic nature of the domain name or the length of the domain name with two character and three character domain names being the most sought after.

The business of registering the domain names as they are deleted by the registries is known as drop catching. It is a highly competitive business. The main operators in this business typically set up a number of front companies as registrars. This ensures that when a domain name is deleted by the registry, the chances of reregistering it are multiplied. The newly reregistered domains are then, more often than not, auctioned off to the highest bidder by these drop catcher companies.

Links

• Premium Name List

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

A domain hack is an unconventional domain name that combines domain labels, especially the top-level domain (TLD), to spell out the full "name" or title of the domain, making a kind of pun.

For example the second-level domain (SLD) blo.gs makes use of the TLD .gs (South Georgia and the South Sandwich Islands) to spell "blogs". The third-level domains del.icio.us and cr.yp.to make use of the SLDs icio.us and yp.to from the TLDs .us (United States) and .to (Tonga) to spell "delicious" and "crypto" respectively.

In this context, the "hack" represents a clever trick (as in programming), not an exploit or break-in (as in security).

Shorter domain names

Domain hacks offer the ability to produce extremely short domain names. A popular real world example is blo.gs with five letters total, versus the comparable blogs.com with eight letters or the often preferred www.blogs.com with eleven letters. Domain hacks default to the omission of the www. prefix, with the side effect of shortening the domain name, as every letter is taken into account as the site's title.

History

On Monday, November 23, 1992, inter.net was registered [1]. On Friday, May 3, 2002, icio.us was registered to create del.icio.us, the most visited domain hack, with the prepending of the "del" third-level domain.

Yahoo! acquired blo.gs[2] on June 14, 2005, and del.icio.us[3] on December 9, 2005.

Who.is is a whois server, indicating the registered ownership information of a domain. It was established June 12, 2002 and registered to an address in Reykjavík as the .is extension is nominally Iceland.

Whocalled.us, a consumer-complaint site listing telephone numbers of known telemarketers, was first registered in 2005.

Other languages

Domain hacks are by no means restricted to the English language.

Some years ago, a passing fad amongst French-speakers was to register their names in the Niue TLD .nu, which led to so-and-so.NU, which in French and Portuguese means "nude" or "naked"; however, as of 2007, Niue authorities have revoked many of these domain names. Likewise, Dutch, Swedish and Danish speakers sometimes use .nu, as it means 'now' in these languages.

Another French-speaking example is teu.be, where "teube" can be translated by "dumb" or "dick" in English. Louez.ça, which means «rent that», is a listing of rental properties in Montréal, Canada.

German examples are Schokola.de (chocolate), Autom.at or fals.ch (wrong).

Some organisations situated in Switzerland uses TLDs to specifically refer to their canton (like the Belgian TLD .be for the Canton of Berne).

An Afrikaans example is dieInter.net - "die" meaning "the" in English (The Internet). Email addresses in this domain can then be expressed as "user at the internet".

A Portuguese example is vai.lá, which is equivalent to the go.to in English. Another is notici.as, where «noticias» means "news".

In Russian, the perevodov.net ("No translations") is a translation portal.

In Slovak, rozbaľ.to ("Unpack it") is the home page of a prepaid Internet access service.

In Slovenian, the najdi.si ("Find it yourself") is a popular local search engine.

A Gibraltarian example is gibtele.com - The phone company in Gibraltar is called Gibtelecom and they have used the .com to their advantage.

Criticisms

Using domain hacks weakens the usefulness of country code TLDs. With domain hacks, it becomes harder to judge the country of origin of a website by just looking at the TLD. Breaking up a domain name to subdomains and/or the URL pathname most often renders the actual domain name meaningless and breaks against good naming conventions.

Some domain hacks are difficult to remember until you become familiar with them, such as del.icio.us. A common typo is to type the periods in the incorrect location. (To counteract this, del.icio.us has also registered the delicious.com and delicio.us domain names which forward to their site.)

Links

Searches

• Domain Hacks - domain hack search utility

Suggestions

• Domain Hacks Suggest - 300,000+ domain hack suggestions (filtered by first letter, word length, and TLD)
• Domain hunting - 220,000+ domain ideas (requires executing a Perl script to generate domain hack suggestions)

Articles

• Domain Hacks & Email Hacks - domain hacks (and "email hacks") explained
• Non Dot Com Cool Domain Names
• Domain Hacks: Inventive or Poor Attempt at Being Cool? Domain hacks examined in depth by doma.in writers
• List of domain hacks
• Coolest Hostnames on the Net (1997) list of classic domain hacks & strange hostnames & email addresses

Registration & Hosting

• V3
• Websear.ch
• family domain name (.fami.ly)
• Arpegg.io

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

A name generator is a program that uses language rules or word combining techniques to generate a list of names. Name generators are sometimes created with specific uses in mind ranging from marketing professionals who may use the generated names to brainstorm brandable product name ideas; through to people seeking an unusual baby or pet name.

Domain name generator

Registering a meaningful domain name has become problematic as most of the dictionary words are already registered by organizations or individuals. Unique meaningful word combinations not already registered are becoming more difficult to choose. The introduction of alternative Generic top-level domains solved the problem partially; however, most of the businesses still prefer the ".com" extension. The are several different strategies for selecting a good domain name: incorporating company's name or its abbreviation into the domain name, use some industry-specific word or a phrase, or use a short and easy to memorize name. These strategies are usually employed by domain name generators that combine a key word provided by the user with a database of prefixes and suffixes. A domain name generator creates a list of names and simultaneously queries the Whois database to see whether the resulting names still have unregistered domains. Such tools are also used by domainers hoping to find domains that can later be traded in the domain name aftermarket.

Fictional name generators

Another type of name generator is that which creates names for people and characters as used by authors, role players and wargaming scenarios. This type of name generator may create a name of specific nationality by combining typical given name and family names together. More sophisticated rules may create the female form of family name as used in countries such as Russian and Greece. Other generators may create totally fictional names based on syllabals arranged by formula in such a way that they create the right sound for a genre: elf names, troll names, Dickensian names etc.

Baby name generators

Parents choosing a name for their offspring or someone choosing a name for a pet might consider family tradition or consult lists of popular given names. Others will get inspiration from name generators that either randomly suggest given names or create names based on combinations of syllables.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Parked domain name for sale

Domain parking is an advertising practice used primarily by domain name registrars and internet advertising publishers to monetize type-in traffic visiting an under-developed domain name. The domain name will usually resolve to a page containing relevant advertising listings and links. These links will be targeted to the predicted interests of the visitor and may change dynamically based on the results that visitors click on. Usually the domain owner is paid based on how many links have been visited (e.g. pay per click) and on how beneficial those visits have been. The keywords for any given domain name provide clues as to the intent of the visitor before arriving.

Another use of domain parking is to be a placeholder of an existing web site. A company might choose to use this method to redirect its website traffic to another web site it owns.

Expired domains that were formerly websites are also sought after for domain parking. A domain that was used as a website and is allowed to expire will still maintain most of its prior inbound links. These types of domains usually start off with their largest amount of visitor traffic initially after being claimed from the domain drop lists. As website operators and search engines begin to remove the former inbound links, the traffic to the parked domain will begin to decline.

On domains with a 'one-click' implementation, a click on a keyword is not necessary to generate ads. The ads are targeted based on the domain name.

Domains with 'two-click' implementations require a click on a keyword or a keyword search to generate ads.

Domain parking can be classified as monetized and non-monetized. In the former, ads are shown to visitors and the domain is 'monetized'. In the latter, an "Under Construction" or a "Coming Soon" message is put up on the domain. This a single page web site that people see when they type the domain name in a web browser. This is one quick way for getting an Internet presence. Domain names can be parked before a web site is ready for launching.

There are several companies that actively cater to domain name owners and act as middlemen to serve advertisements on parking pages. The parking pages are propagated automatically on a domain owner's web property when they either change the name servers or forward the URL.

Links

• The Death of Domain Parking?, from Slashdot.org

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Video: Reviews of Domain Parking Services

An incorrectly entered URL could lead to a website operated by a cybersquatter.

Typosquatting, also called URL hijacking, is a form of cybersquatting which relies on mistakes such as typographical errors made by Internet users when inputting a website address into a web browser. Should a user accidentally enter an incorrect website address, they may be led to an alternative website owned by a cybersquatter.

Generally, the victim site of typosquatting will be a frequently visited website. The typosquatter's URL will usually be one of four kinds, all similar to the victim site address:

(In the following, the intended website is "example.com")

• A common misspelling of the intended site: exemple.com
• A misspelling based on typing errors: xample.com or exxample.com
• A differently phrased domain name: examples.com
• A different top-level domain: example.org

Once in the typosquatter's site, the user may also be tricked into thinking that they are in fact in the real site; through the use of copied or similar logos, website layouts or content. Sometimes competitors of the victim site will do this.

Alternatively, the user will be forwarded to a site of a completely different nature to what they intended. This tactic was infamously used by John Zuccarini, who redirected domains targeting children to pornographic websites. Sometimes, the typosquatters will use the false addresses to distribute viruses, adware, spyware or other malware. Some are also shock sites. More common are benign domain parking sites, selling advertising to firms based on keywords similar to the misspelled word in the domain.

As with cybersquatting in the past, the term typosquatting has been used by covetous parties in an effort to unseat domain registrants from brandable variants of generic domain names. The shortage of poignant and generic domain names in the coveted .com generic top-level domain has left many hopeful registrants with no alternative but to locate catchy variants of existing generic words e.g. Orbitz.com (popular travel site with "z" to replace the "s") in an effort to find "new land" on which to build their website. As in the preceding example, the line between typosquatting and registering a brandable variant of a generic domain name blurs dependent on the circumstance of each situation.

Links

• The man who owns the Internet - (CNNMONEY.com, May 22 2007) This article is about Kevin Ham the man responsible for the Cameroon .cm wild-card redirect ploy.
• The Typo Millionaires (Slate, 11 February 2005) - This article's author identifies new forms of typosquatting, including VeriSign's Site Finder and Paxfire.
• Slashdot discussion, Google Wins Typosquatting Dispute.
• "Typosquatting A Growth Industry"
• Strider URL Tracer with Typo-Patrol at Microsoft Research
• Strider Typo-Patrol Project at Microsoft Research
• Typosquatting and the .eu Top-Level Domain' (Droit-technologie.org, June 26, 2007)

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Need an webmaster? Click HERE

Turning a website into an income source is a common practice for web-developers and website owners. There are several methods for creating a website business which fall into two broad categories.

1. Online Information Businesses

Some websites offer no products at all but provide free information with income coming from clicks the visitors make on advertisements (see contextual ads). There is a wide range of monetizing used on such sites and the sites themselves are actively traded and bought and sold as going concerns.

Guides have been published which explain how to create such a business. See links at bottom of page.

2. Online Shop Businesses

While most business websites serve as a shop window for brick and mortar businesses it is increasingly the case that some websites are businesses in their own right. These websites are fully self-contained businesses entities offering, for example, immediate downloads of retail software on payment of the product's price via their shopping cart.

Guides have been published which explain how to create such a business. See links at bottom of page.

3. Online Services Businesses

It offers a lot of services in every field, such as, tourism, economic, politic, social welfare.

Spelling

As noted above, there are several different spellings for this term. Although "website" and "web site" are commonly used (the former especially in British English), the Associated Press Stylebook, Reuters, Microsoft, academia, book publishing, The Chicago Manual of Style, and dictionaries such as Merriam-Webster use the two-word, initially capitalized spelling Web site. This is because "Web" is not a general term but a shortened form of World Wide Web. As with many newly created terms, it may take some time before a common spelling is finalized. (This controversy also applies to derivative terms such as "Web master"/"webmaster" and "Web cam"/"webcam").

The Canadian Oxford Dictionary and the Canadian Press Stylebook list "website" and "web page" as the preferred spellings. The Oxford English Dictionary began using "website" as its standardized form in 2004.^[2]

Bill Walsh, the copy chief of The Washington Post's national desk, and one of American English’s foremost grammarians, argues for the two-word spelling with capital W in his books Lapsing into a Comma and The Elephants of Style, and on his site, the Slot. ^[3]

Way to Upload website and earn on click basis

Here are some guidelines to make a website for earning pupose.

Types of websites

There are many varieties of Web sites, each specializing in a particular type of content or use, and they may be arbitrarily classified in any number of ways. A few such classifications might include:

• Affiliate: enabled portal that renders not only its custom CMS but also syndicated content from other content providers for an agreed fee. There are usually three relationship tiers. Affiliate Agencies (e.g., Commission Junction), Advertisers (e.g., Ebay) and consumer (e.g., Yahoo).
• Archive site: used to preserve valuable electronic content threatened with extinction. Two examples are: Internet Archive, which since 1996 has preserved billions of old (and new) Web pages; and Google Groups, which in early 2005 was archiving over 845,000,000 messages posted to Usenet news/discussion groups.
• Blog (or web log) site: sites generally used to post online diaries which may include discussion forums (e.g., blogger, Xanga).
• Corporate website: used to provide background information about a business, organization, or service.
• Commerce site or eCommerce site: for purchasing goods, such as Amazon.com.
• Community site: a site where persons with similar interests communicate with each other, usually by chat or message boards, such as MySpace.
• Database site: a site whose main use is the search and display of a specific database's content such as the Internet Movie Database or the Political Graveyard.
  Development site: a site whose purpose is to provide information and resources related to software development, Web design and the like.
• Directory site: a site that contains varied contents which are divided into categories and subcategories, such as Yahoo! directory, Google directory and Open Directory Project.
• Download site: strictly used for downloading electronic content, such as software, game demos or computer wallpaper.
• Employment site: allows employers to post job requirements for a position or positions and prospective employees to fill an application.
• Erotica websites: shows sexual videos and images.
• Game site: a site that is itself a game or "playground" where many people come to play, such as MSN Games ,Pogo.com and Newgrounds.com.
• Geodomain refers to domain names that are the same as those of geographic entities, such as cities and countries. For example, Richmond.com is the geodomain for Richmond, Virginia.
• Gripe site: a site devoted to the critique of a person, place, corporation, government, or institution.
• Humor site: satirizes, parodies or otherwise exists solely to amuse.
• Information site: contains content that is intended to inform visitors, but not necessarily for commercial purposes, such as: RateMyProfessors.com, Free Internet Lexicon and Encyclopedia. Most government, educational and non-profit institutions have an informational site.
• Java applet site: contains software to run over the Web as a Web application.
• Mirror (computing) site: A complete reproduction of a website.
• News site: similar to an information site, but dedicated to dispensing news and commentary.
• Personal homepage: run by an individual or a small group (such as a family) that contains information or any content that the individual wishes to include.
• Phish site: a website created to fraudulently acquire sensitive information, such as passwords and credit card details, by masquerading as a trustworthy person or business (such as Social Security Administration, PayPal) in an electronic communication. (see Phishing).
• Political site: A site on which people may voice political views.
• Pornography (porn) site: a site that shows pornographic images and videos.
• Rating site: A site on which people can praise or disparage what is featured (e.g. ratemyrack.com).
• Review site: A site on which people can post reviews for products or services.
• Search engine site: a site that provides general information and is intended as a gateway or lookup for other sites. A pure example is Google, and the most widely known extended type is Yahoo!.
• Shock site: includes images or other material that is intended to be offensive to most viewers (e.g. rotten.com).
• Warez: a site filled with illegal downloads.
• Web portal: a site that provides a starting point or a gateway to other resources on the Internet or an intranet.
• Wiki site: a site which users collaboratively edit (such as Wikipedia).

Some websites may be included in one or more of these categories. For example, a business website may promote the business's products, but may also host informative documents, such as white papers. There are also numerous sub-categories to the ones listed above. For example, a porn site is a specific type of eCommerce site or business site (that is, it is trying to sell memberships for access to its site). A fan site may be a dedication from the owner to a particular celebrity.

Websites are constrained by architectural limits (e.g., the computing power dedicated to the website). Very large websites, such as Yahoo!, Microsoft, and Google employ many servers and load balancing equipment such as Cisco Content Services Switches to distribute visitor loads over multiple computers at multiple locations.

In January of 2007, Netcraft, an Internet monitoring company that has tracked Web growth since 1995, reported that there were 106,875,138 Web sites with domain names and content on them in 2007, compared to just 18,000 Web sites in August 1995.

Prizes

The Webby Awards are a set of awards presented to the world's "best" websites, a concept pioneered by Best of the Web in 1994.

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.

Uniform Resource Locator (URL) is a technical, Web-related term used in two distinct meanings:

• In popular usage, it is a widespread synonym for Uniform Resource Identifier (URI) — many popular and technical texts will use the term "URL" when referring to URI;
• Strictly, the idea of a uniform syntax for global identifiers of network-retrievable documents was the core idea of the World Wide Web. In the early times, these identifiers were variously called "document names", "Web addresses" and "Uniform Resource Locators". These names were misleading, however, because not all identifiers were locators, and even for those that were, this was not their defining characteristic. Nevertheless, by the time the RFC 1630 formally defined the term "URI" as a generic term best suited to the concept, the term "URL" had gained widespread popularity, which has continued to this day.

URI/URL syntax in brief

Every URI (and therefore every URL) begins with the scheme name that defines its namespace, purpose, and the syntax of the remaining part of the URI. Most Web-enabled programs will try to dereference a URI according to the semantics of its scheme and a context-vbn For example, a Web browser will usually dereference a http://example.org/ by performing an HTTP request to the host example.org, at the default HTTP port (see Port 80). Dereferencing URI mailto:bob@example.com will usually open a "Compose e-mail" window with the address bob@example.com in the "To" field.

"example.com" is a domain name; an IP address or other network address might be used instead.

URLs as locators

In its current strict technical meaning, a URL is a URI that, “in addition to identifying a resource, [provides] a means of locating the resource by describing its primary access mechanism (e.g., its network ‘location’).”^[1]

Links

• Cool URIs don't change
• Why you should be using disambiguated URLs
• RFC-3986 Uniform Resource Identifier (URI): Generic Syntax
• RFC-3986 (html)

This guide is licensed under the GNU Free Documentation License. It uses material from the Wikipedia.