A Uniform Resource Identifier ( URI ) is an identifier and consists of a string identifying an abstract or physical resource is used. URI ‘s are used for identification of resources (such as websites , other files, calling web services , but also, for example, e-mail recipients) in the Internet and there, especially in Web use.

Originally, Tim Berners-Lee the concept in 1994 in RFC 1630 as a Universal Resource Identifier one. Only later appeared then in official W3C documents, the resolution uniform on. For this reason, universal occasionally – even in the scientific literature – the first part of their name called as.

URIs can be used as a string (encoded with a character set ) into digital documents, especially those in HTML format or incorporated by hand on paper to be written. A reference from a Web page to another is called a hyperlink or just link.

An extension of the only printable ASCII -character- URIs are Internationalized Resource Identifiers (IRIs).

DNS names are in domains managed. , DNS names on the Internet known to make a condition that is registering the corresponding domain .

In principle, participants are on the internet without a domain name – containing the correct IP address is sufficient in most cases. The numeric IP addresses can be severe but generally remember clearly as a meaningful name. In addition, a domain also other advantages such as accessibility at the same address, even after switching the server, virtual host name and load balancing via DNS . own name server available to do so or is the prerequisite for a successful web presence.

A simple and cheap way is to an existing domain registered in a subdomain. Suppose the fictitious company example GmbH uses the domain of their service provider ISP . Then could the domain name like this: www.example-gmbh.isp.com . Registration is not required here, since in principle (with some exceptions) to register domains that are directly below a top level domain lie.

Registration Organizations

A Network Information Center (or shortly Registry) is an organization, the domains managed. A domain name registrar acts as an interface between the Registry and the Registrant.

As a registrant of the end customer is known, so anyone who actually wants to register a particular domain. For legal or other reasons, this designation may be unusual nationally, in Germany we speak for example of the domain holders

Connectivity

Domain registration alone is not enough domain names to publish on the web. First, each domain on one or more name servers in a zone file to be present. Then in the zone that the parent domain, contains a reference (Delegation) name servers are registered on this.

With domain registration are therefore always in the parent name servers associated entries. The required NS resource records with the Registrar in conjunction with the authoritative registry in the parent server automatically considers normal. When registering, the client must do the – mostly from his own or made ​​available to providers – indicate the name servers that are authoritative, the new domain fold lines. In general, the registrar checks prior to registering this information in order to ensure that the delegation did not show ineffective.

For smaller domains, which are very few resource records included, can in some top-or second-level domains (such as. com) name server may be dispensed to separate. The resource records can be a domain registrar in its own name servers are deposited directly from.

Before a registration need clarification

Select a name

First, the name of the domain and the parent domain (usually a top-level domain such as. com or. en) be established. It should be examined to assess the possible rights of third parties (such as registered trademark). In each name can be letters, numbers or hyphens are included, between upper and lower case is not being made. The detailed rules (eg “name can not begin with a hyphen”) is before the Registrar. Depending on top-level domain registrar and other special characters may be used.

About the Whois service can be determined whether the desired domain name is available at all. Many providers offer this on your website more or less extensive query tools. The country-specific registration organ Istat ions also offer possibilities to check whether a domain has already been awarded. However, each domain there is usually only one’s own included. DENIC published, for example, only information about domains, with. Com ending.

Some top-level domains (TLDs), there are limitations that may prevent registration. must have, for example, in the. com and. fr-TLDs the applicant or his representatives administrative (admin-c) a postal address within the country concerned. A similar situation is also apply for. Eu domain. The nationality of the applicant does not matter.

Selection of a registrar or service provider

There are usually several ways to register its domain:

• through a direct contract with the operator of a (top level) domain (often expensive, often not easy, sometimes only as a major customer)
• with a registrar for the desired major domain
• a registrar with a collaborating service provider
• through a reseller or distributor who works with a service provider or registrar

For individuals and small businesses most service providers or their resellers are preferred because they are much cheaper and the service provider tedious detail work takes over and provides many essential services plus domain registration from a single source. As a guideline for the cost of registration in the German-speaking popular domains can go out every year by about 0 to 100 € for the registration and 6 to 180 € for the care. This varies with the top-level domains and with the service providers, as well as the volume of services they provide.

Setting up the server name

In addition, clarify who operates the name servers, which are on the future domain is. This could be your own server, or managed by an Internet Service Provider. If only a few DNS names required may be waived in some registries to operate their own name servers. The names are then registered to the name server of the Registry. DENIC allows, for example in such cases, up to five names for each domain.

The Name Server  must normally be available at the time of registration and the new domain already mentioned. Also, the name server itself to be registered. Responsible for the registration of which is the owner of the parent domain. Thus, for example, the registration of the name server ns1.example.com by the holder of the domain example.com will be carried out.

Expiry of a registration

A domain registration is done online via the Web interface, a proprietary application or through traditional forms which, by or by post sent to fax it. Some operations, such as deleting the domain or a trade, but can be performed automatically in many cases, but require a signed form.

When registering the name of the domain holder, and various administrative and technical contact shall be identified, also their mailing addresses. It should be noted that this information according to local data protection provisions of the Whois service can be accessible to everyone.

Simultaneously with the domain registration addresses some DNS name and IP registered. Normally, two or more NS records and any necessary glue records . For individuals or small businesses without their own name servers, some few A – and MX – RRs the name server of the registrar to be managed well.

The arrangements are from the registry. DENIC example, calls for at least two name servers must also be in different subnets. Other registries are or were less restrictive.

Many customers register a domain only with the option to park it (not to use) or sell on. There are services that provide for such temporary purposes Name Server.

By registering a domain legal impact associated.

Registration period

Registrations are limited in time principle. A domain can not buy “will”. Common in the first registration period is one year, at the end of which automatically renew. Most domains (not. De and. Eu) have larger intervals up to ten years also. Expire domain – because the payments fail about – it is a 30 days or more continuous blocking state set in (English: redemption grace period ), in which the owner has the opportunity to reactivate them. If reactivation of the will they finally released after about five days.

Subsequent changes

No changes to the registry data is usually carried out online. Through a password-secured Web access, the data can be edited by the holder at any time. Be a difficult operation is the domain transfer , a domain is transferred to another registrar in the. The latter is often referred to as Provider-exchange, since the domain transfer almost always from a service provider to another domain is transferred to the new registrar or at the same time, the new service provider is.

Anonymous registration

A controversial issue within the current registration practice is to publish personal information about domain owner and its administrative and technical representation in the central database of the relevant top-level domain. Information such as postal address or e-mail address of the Whois service by anyone and therefore potentially available to the abuse, such as professional address collectors suspended. On the other hand, in case of possible violations of the domain owner (such as improper registration of foreign brand names) that are legally available, in particular, have a serviceable address also.

A compromise solution to the anonymous registration. The registrar will use his own data or data from third parties instead of the customer information. Through a special contractual relationship of the anonymous customer is still owned the domain, even if it is not even listed in the Whois database. The Registrar acts as trustee on behalf of customers.

For some TLDs, such as for. Ch (Article 2.5 and 3.2 SWITCH GTC), there is an obligation on the part of the registrant’s right to disclose identity. If not, can the registry delete the domain name.

Historically important domains

The world’s first registered domain was nordu.net , it was the first January 1985 registered.

The company Symbolics registered on 15 March 1985 symbolics.com the first. com domain. In 1985, a total of six. Com domains registered , 1986 54 and 1987 47th

Whois ( “who is” ) is a protocol , with that of a distributed database system, information about internet domains and IP addresses and their owners can be queried.

Whois -queries since its inception in particular on the command line performed. As appropriate client software is not available for all major operating systems, was set up early Web-based front end through. Despite subsequent versions corresponding to enjoy Web-Whois provider is still very popular, not least for reasons of relevance to domain lookups.

The term “Whois” is for other, similar queries used, for example, user information in the IRC on.

Protocol

In the by the IANA defined port 43 / TCP protocol is a plain text defined. The sister protocol rwhois extended Whois for redirects and a hierarchical structure, similar to the Domain Name System . Queries are as in HTTP 0.9 from a single line by the client to an open socket is passed. On the first line feed follows the response of the Whois server. Some databases, including allow to specify the encoding or the query type by the custom query prefix, but not normalized parameter. Through its architecture, queries like this example with a Telnet client can be carried out.

History

In the early days of the Internet was the registration and administration of all domains of the ARPANET in the hands of the DARPA . This centralization made ​​it possible to single server information on all assigned IP addresses, domains, and to contact a person. The small number of records also allowed fuzzy search for a name or any content. With increasing in the nets, the addition of new registrars and abuse by spam senders criteria were increasingly restricted. A trend that has continued until today, so today’s Whois query server restrictive quotas define at times and some web Whois service provider by their spelling or ways to protect the bot detection use them.

When the ARPANET in the late 1980s, the Internet opened up, DARPA initially remained as a registrar until the National Science Foundation task was entrusted to commercial third party.

On 1 December 1999, the responsibility of ICANN for the three popular. com,. net and. org domains where a model changed was, that complete records for the respective registrars delegates (“thin”) and traditional clients more restricted just worked. From 1 January 2003 adopted the Public Interest Registry (led by Afilias) operating. org, back in the model of a central data management (“thick”).

Today, with the existence of new generic and sponsored top-level domains and even new country domains is a complex, incomplete plexus, a successful lookup, the domain knowledge of the Whois server requires.

To eliminate existing disadvantages, formed in 2004, an IETF working group to set a new standard with the working title CRISP (Cross Registry Information Service Protocol) to set out. A first result of these efforts is the XML -based IRIS protocol, whose classes RPSL structures recall. Previous attempts to Whois information via LDAP be made ​​available, or the Whois + + were unsuccessful.

Problems

Neither structure and encoding the return still subject to error-handling standards, resulting in machine evaluation difficult cross-domain. Domänenlookups the responsibility of each organization entrusted with the administration or NIC , and are not for every Top Level Domain available. Usually can find detailed information for the domain registration must be specified query. The public provision of telephone numbers in the context of Whois records is subject to constant debate in 2006 by a proposal of the ICANN flared up again. Since an administrative contact for any misuse is also provided , providers are limited, some are already on a list of name servers or information concerning the registrability.

Since there naming conventions for whois servers is no cause common clients such as GNU jwhois correlation with lists that any modification of a configuration updates need to.

List of Whois servers

IP and AS lookups

Databases for IP lookups ( IPv4 and IPv6 ) by the five RIRs ( Regional Internet Registry ) maintained and serviced.

The databases of the Regional Internet Registries are usually available on their websites for download. The information contained in these packets contain information to protect people from abuse no classes.

Details of Autonomous Systems are also provided by the RIRs.

generic Top Level Domains (gTLDs)

The listed servers is whois servers that provide their information on port 43/TCP, but not for the Web front-ends of the respective providers.

Second Level Domain Whois

Chance-level domains can own Whois server running second. In some countries, the. Co.uk “follow similar pattern,” it takes the appropriate NIC. Some commercial providers such as CentralNic (among other things. de.com) ausregistry (among other things. com.au) or info.at (among other things. info.at) make information available Whois.

Query Whois databases

To Whois information is also using Web browsers to make available, there are various Whois proxy services. In many cases, it is of domain registrars operated dealers and services that only a few domains and IP or AS often only cover information. Search for more relevant recommends the use of a client in the command line

In the Domain Name System of the Internet called zone the part of the domain tree for which a name server (also referred to NS) is responsible and therefore knows the official data. A zone is managed by a Primary Name Server. To increase the availability of server failures, it is common to a zone or more secondary name servers to reflect on.

A zone consists of resource records , in a zone file is stored. The original file is located on the primary name server (also called “master”). From there, it is changes by zone transfer the secondary nameservers (also called “slave” is named) transfer. The terms zone and zone file are almost interchangeable in all situations.

A zone, an entire domain include. Normally they are separate sub-domains are represented by zones. With pointers – the NS Resource Records (RR-NS) – becomes sub-zones has pointed to name servers are on the other hand can. This process is called delegation: A zone delegates the responsibility for a subdomain, and only knows the person or persons responsible name server. Subdomain requests to be forwarded to the responsible name server. The transition between two zones is called Cut this area, as a zone of a domain “cut” by a delegation.

The top level domain de contains, for example, including all subdomains millions of DNS records. It is impossible to keep this single zone file in a. The domain of de associated zone file therefore contains mostly references to the direct sub-domains. Pro authoritative name server for a subdomain, while there is a NS record.

Difference between domain and zone

A domain includes the whole child DNS namespace. The term domain is also used if you look at the content (which includes a domain name?) or the title (who is a domain registered?) refers.

A domain can be divided into several zones in by placing the responsibility for sub-domains delegated. Of a zone is referred to even if you think the physical realization – ie which server and zone file in which the DNS records are.

By the juxtaposition of domain names (labels) defined on the domain tree and the NS RRs constructed tree zone are almost identical. In rare cases, a single zone file also contain multiple domains. The area tree is therefore slightly smaller than the domain tree.

IDNA (Internationalizing Domain Names in Applications) is an Internet standard , with domains, the non- ASCII characters, as valid ASCII strings in the domain name system to map. Such a domain name called IDN (Internationalized Domain Name),

Technology

Unicode -domains are the procedures Nameprep and Punycode ASCII strings converted to that as ACE -Strings ( A SCII C ompatible E are called) ncoding. The conversion is done at the client (such as the browser or mail program) so that the server infrastructure need not be changed. Instead of Unicode strings client, the user can directly enter the ACE string. Thus, even without IDN clients Ability to work with international domains, provided the user knows the ACE string. Since this is cumbersome, however, it is recommended only if the software is not IDN-proof reliability.

Basically, all Unicode characters allowed in IDNs. The “beta” was the same as “ss” and declared as the normalization of s converted to, so for example, “splices” was identical with “Pleisse. From 16 November 2010 (after purchasing a domain with ss before) but it is for the modified version of IDNA -up possible to register domains with separate beta, and the mapping to ss is repealed.

Any award for domains separately regulates what characters it for granted by their ( sub -) allowed domains. Since 1 March 2004, in addition to the 37 common characters (26 letters of the Latin alphabet , 10 numerals and the hyphen) for German ( . de ) Second-level domains 92 and for Switzerland (. ch) and of Liechtenstein (. li) domains 31 other characters be used. Since 31 March 2004 for Austrian domains (. at) other characters are allowed 34th Afilias, in charge of. Info domains will allow only the characters, ö and ü to ä.

Processing of Unicode strings

First domain is a Unicode Nameprep normalized by, ie capital letters to lowercase letters and characters are defined as equivalent to the normal form (ASCII) into. In the old version of IDNA was ß to ss equivalent, so we were in street road .

Following the normalization letters are Punycode non-ASCII name removed from the end of the name and any derivative ASCII string added to one, in which the position and nature of the Unicode character is encoded. An IDN-ASCII domain names to distinguish them from one, begins with the prefix string Punycode xn - . The unusual string xn - has been chosen because they real words or proper names not present in practically and conflicts with ASCII domains, therefore, extremely unlikely.

Fonts

Below is listed for some top-level domains, which non-ASCII characters are allowed in the respective IDN domains:

. De domains

A A A A A A A æ å ä ć ç ď đ ĉ ċ č é è ĕ ê ë ì ë E E G G G G H H I I I I I I I I I J K L L L L N N N n N o o o o o o o o o ĸ œ R R R S S S S ss ť ţ ŧ ú ù u u u u u u u u w ý ŷ ÿ ź ż ž ð þ

. Eu domains

A A A A ä å æ ç è é ê ë ì í î ï ð ñ ò ö ø ù ó ô õ ú û ü ý þ ÿ ā ă ą ć ĉ ċ č ď đ ē ĕ ė ę ě ĝ ğ ġ ģ ĥ H I I I I I J K L L L L L N N N N o o o ʼn œ R R R S S S T T U u u u u w y z ž ż ş ţ ΐ ά έ ή ί ΰ α β γ δ ε ζ η θ ι κ λ μ ν ξ ο π ρ ς σ τ υ φ χ ψ ω ϊ ϋ ό ύ ώ а б в г д е ж з и й к л м н о п р с т у ф х ц ч ш щ ъ ы ь э ю я ἀ ἁ ἂ ἃ ἄ ἅ ἆ ἇ ἐ ἑ ἒ ἓ ἔ ἕ ἠ ἡ ἢ ἣ ἤ ἥ ἦ ἧ ἰ ἱ ἲ ἳ ἴ ἵ ἶ ἷ ὀ ὁ ὂ ὃ ὄ ὅ ὐ ὑ ὒ ὓ ὔ ὕ ὖ ὗ ὠ ὡ ὢ ὣ ὤ ὥ ὦ ὧ ὰ ά ὲ έ ὴ ή ὶ ί ὸ ό ὺ ύ ὼ ώ ᾀ ᾁ ᾂ ᾃ ᾄ ᾅ ᾆ ᾇ ᾐ ᾑ ᾒ ᾓ ᾔ ᾕ ᾖ ᾗ ᾠ ᾡ ᾢ ᾣ ᾤ ᾥ ᾦ ᾧ ᾰ ᾱ ᾲ ᾳ ᾴ ᾶ ᾷ ῂ ῃ ῄ ῆ ῇ ῐ ῑ ῒ ΐ ῖ ῗ ῠ ῡ ῢ ΰ ῤ ῥ ῦ ῧ ῲ ῳ ῴ ῶ ῷ

. Com and. Net domains

à á â ã ä å æ ç A A A C C C C D đ è é ê ë ē ĕ ė ę E N D G G G G H H I I I I I I I I I J ķ ĸ l l l l n n n n o o o o o o o o o o r R R S S S S T T T þ ù ú û ü ũ ū ŭ ů ű ų w ý ÿ ŷ Ÿ ž ż

. Info domains

ä æ å á é í ñ ð ó ö ø ú ü ý þ â ± ć č ę ė ē ģ ī į ķ ļ ł ń ņ ő ō R S š u u u ź ż ž

. At domains

A A A A ä å æ ç è é ê ë ñ ð ì í î ï ò ö ø ó ô õ œ š þ ù ú û ü ý ÿ ž

. Ch and. Li domains

A A A A ä å æ ç è é ê ë ñ ð ì í î ï ò ö ø ó ô õ œ þ ù ú û ü ý ÿ

. Org domains

ä ö ü

Since May 2010, there is also IDN top-level domains , and thus complete domains from non-Latin letters. There are, for example, the top-level domain مصر for. that the Arabic word Egypt ( Misr is) the home page the Egyptian Ministry of Communications and Information Technology is the exclusive domain of Arab-character http:// موقع -. وزارة الاتصالات. مصر reach. The domain name is the Arabic from right to left to read accordingly

A WhoIs query of the form whois.denic.de whois-h --C ISO-8859-1 example.com or whois-h whois.denic.de - C-UTF-8 example.com to Unicode-based systems provides for registered domains including the spelling in Punycode.

Support through web browser

IDNs To use, make sure your client, such as a browser be able to in the URL line entered the international domain name (for example, umlauts) in an ACE string to convert.

Some of IDN-enabled browsers:

• Firefox Version 0.8
• Konqueror from KDE 3.2 with GNU IDN Library
• Windows Internet Explorer , version 7.0 (*)
• Mozilla version 1.4
• Netscape Navigator Version 7.1
• Opera from version 7.11
• Safari version 1.2 (v125)
• SeaMonkey 1.0 and

(*) Internet Explorer (IE) may, from version 5.0, by installing the plug-ins i-nav VeriSign Pictures) due to be made ​​capable IDN see (. Connect with IE 6 but despite this plug-in occasionally faulty processes on. An alternative to i-nav offers the RFC-compliant plug-in Quero Toolbar (see References), the IDN phishing protection mechanisms is equipped with it.

Review

Critics say the introduction of IDNs is a historic mistake in the development of the Internet was. IDNs are a result of country-specific keyboard designs for large parts of the network population is not achievable in practice, thus deepening the rifts between the language areas and counter-checked the Internet ultimately the underlying concept of the “global village”. This will be the application behind the IDN introduction idea, especially the language areas with non-Latin characters (for example Arabia, East Asia) to integrate more into the grid, led ad absurdum.

The proportion of IDNs to all registered domains under . com is about three and a half percent.