American Standard Code for Information Interchange, ASCII , alternative US-ASCII , is a 7-bit character encoding , and corresponds to the U.S. variant of ISO 646 and serves as a basis for future more bits based encodings for fonts .

The ASCII coding was on 17 June 1963 as a standard ASA X3.4-1963 and 1967 and published recently in 1968 (ANSI X3.4-1968) updated. The encoding defines 128 characters, consisting of 33 non-printable and 95 printable. The latter are, starting with the space :

The printable characters include the Latin alphabet in upper and lower case, the ten Arabic numerals and some punctuation marks and control characters . The character set is similar to that of a keyboard or typewriter for the English language . In computers and other electronic devices, text constitute, he is usually referred ASCII or backwards compatible ( eight thousand eight hundred and fifty-nine ISO , Unicode to store).

The non-printable characters output characters such as newline or tab, log -like character transmission is complete, or confirm and separating characters such as record delimiters.

Encoding

Each character is a bit pattern of 7 bits assigned. Because each bit can assume two values, there are 2 ⁷ = 128 different bit patterns, also known as the integers 0-127 (hex 00-7F) may be interpreted.

In non-English languages ​​used special characters – such as German umlauts – bit code can not be fully represented with the 7, it would require at least 8 bits. The data processing used in Rule 8 bit or a byte as the smallest unit for data storage. The most significant bit in each byte is ASCII using the value 0 is set at.

It can also use error correction ( parity ) communication lines or for other control functions to be used to. Today it is almost always extending ASCII to an 8-bit code used to. These extensions are largely with the original ASCII compatible , so all characters defined in the different enhancements of the same bit patterns are encoded in ASCII. The extensions vary depending on hardware and software and are country specific.

History

One form of the character encoding was the Morse code . He was with the advent of telegraphs the telegraph networks and forced out by the Baudot code and code-Murray replaced. From the five-bit code to the Murray-seven-bit ASCII, it was then only a small step – even ASCII was first American telegraph certain models, such as the Teletype ASR33 used for. In the early days of the computer age evolved into the standard ASCII code for characters. As an example, many were terminal ( VT100 ) and printer with ASCII only be controlled.

ASCII was originally the representation of characters of the English language. The first version, still with no lower case and with small deviations from the current ASCII was created in 1963. In 1968, the day before valid ASCII set then. later other languages ​​to represent special characters can order (for example, German umlauts), adopted new codes with eight bits per character as ASCII-compatible basis. However, also offered an eight-bit code in which a byte is a character stood for, too little space to all the signs of human culture are simultaneously written to accommodate. Thus, several different specialized extensions necessary. There are also all for the Far East some ASCII-compatible encoding, either between code tables switch or on more than one byte for non-all ASCII characters need before. None of these eight-bit extensions “is” ASCII, because that means only the single seven-bit code.

For encoding characters in the Latin is almost exclusively mainframe computers incompatible with an ASCII encoding used ( EBCDIC ).

Composition

The first 32 ASCII character codes (from 00 to 1F) are for control character (control character) reserved; see there for the explanation of the abbreviations in the table above. They are characters, no characters represent, but to control such devices are used by (or used) that use the ASCII (such as printers). Control characters are eg the carriage return to newline or Bell (the bell), and their definition is historically justified.

Code 20 (SP) is the space (English space or blank ), in a text as empty words and delimiters used between and on the keyboard using the space bar is created.

The codes 21 to 7E are all printable characters of letters, numbers and punctuation characters (see table) included.

Code 7F (all seven bits set to one) is a special character as a delete character is referred to ( DEL ) . This code was used as a control character used to refer to paper tape or punch cards already punched characters subsequently a setting with all the bits, that is, by Auslochen all seven markers, delete can be – once existing holes can be more eventually not be undone. Areas without holes (ie, code 00) were found mainly at the beginning and end of a perforated strip ( NUL ) .

For this reason, only 126 belonged to the actual ASCII characters, because the bit pattern 0 (0 million) and 127 (1111111) met no character codes. The code 0 was later in the programming language C as the end of the string ‘interpreted, the sign 127 were assigned to different graphic symbols.

Extensions

ASCII does not contain diacritical marks to all the languages ​​on the basis of the Latin alphabet are used in almost. The international standard ISO six hundred forty-six (one thousand nine hundred seventy-two) was the first attempt to address this problem, which led to compatibility problems, however. He’s still a seven-bit code, and because no other codes were available, were used some code in new versions.

For example, the ASCII position 93, the right to square bracket (]) in the German character set variant ISO 646-DE by the big U with umlaut dots (R) and the Danish variant of ISO 646-DK by the large A with ring ( Krouzek ) (a) ‘. When programming staples had to be used in many programming languages ​​the square by the respective national characters are replaced. This reduced the readability of the code and often led to unintended comic results by about the startup of the Apple II “APPLE] [" from "APPLE ÜÄ" mutated.

Several manufacturers developed their own eight-bit code. The code page 437 code has long been called the most widely used, he came to the IBM-PC under English MS-DOS , and is still in the DOS window by English Microsoft Windows used. In the German installations, since MS-DOS 3.3, the Western European code page 850 is the default.

Even in later standards such as ISO 8859 , eight bits used. Here are several variants, such as ISO 8859-1 for the Western European languages. German-language versions of Windows (except DOS window) to use the ISO 8859-1 encoding anabolic Windows 1252 - see, for example, text files created under DOS, the German characters from wrong, therefore, if you look under Windows.

Many older programs that used the eighth bit for their own purposes, could not handle it. They were often adjusted over time the new requirements.

To meet requirements of different languages ​​to be, the Unicode (his character repertoire in identical with ISO 10646 ) developed. It uses up to 32 bits per character, and could be four billion different characters differ is over, but at about one million allowed code points limited. This can all previously used characters are represented by people, unless they were taken to the Unicode Standard in. UTF-8 is an 8-bit encoding of Unicode that is backward compatible with ASCII. A character can be one to four 8-bit words are taking. Seven-bit versions must not be used, but can also use Unicode UTF-7 bit encoding, seven in. UTF-8 evolves (2011) for a uniform standard on most operating systems. The users include Apple's Mac OS X and some Linux distributions UTF-8 and more and more websites are by default UTF-8 in created.

ASCII contains only a few characters that are generally binding, format or structure of text to be used, which went from the commands of the Telegraph shows. In particular these include the newline (line feed), the carriage return (carriage return), the horizontal tab , the feed (form feed), and the vertical tab. In typical ASCII text files can be found next to the printable characters usually only the carriage return or line feed to mark the end of the line, be it in DOS and Windows systems usually both used in succession, with older Apple - and Commodore computers (without Amiga ), only the carriage return and on Unix -like, and Amiga systems, only the line feed. The use of additional characters for text formatting is handled differently. For formatting text are now more markup languages ​​such as HTML used.

Compatible character encodings

Many encodings are designed so that characters in the range 0 ... 127 use the same code as ASCII and the area over 127 more characters to use.

Fixed-length codes (selection)

Here is a fixed number of bytes for one character. In most codes this is one byte per character, per the East Asian fonts in two or more byte characters.

• ISO 8859 with 15 different character encodings to cover all European languages, Turkish , Arabic , Hebrew , and Thai
• MacRoman , MacCyrillic and other proprietary fonts for Apple Mac computers from Mac OS X.
• Windows and DOS code pages , Windows 1252
• KOI8-R for Russian, KOI8-U for Ukrainian
• ARMSCII-8 and 8a-ARMSCII for Armenian
• GEOSTD for Georgian
• ISCII for all Indian languages
• TSCII for Tamil

Variable-length codes

In order to be able to encode more characters, the characters are coded 0 ... 127 in a byte, other characters are encoded by multiple bytes with values ​​of over 127th

• UTF-8 for Unicode
• Big5 for Traditional Chinese ( Taiwan , overseas Chinese)
• EUC (Extended UNIX Coding) for several East Asian languages.
• GB (Guojia Biaozhun) Simplified Chinese ( PRC )

ASCII table

The ASCII table contains all the codes of the ASCII character set, see control characters for the meaning of the abbreviations:

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).

The Internet Corporation for Assigned Names and Numbers ( ICANN ) is a private non-profit organization of U.S. law, established in California City Marina del Rey .

Task

ICANN decides on the basis of the management of top-level domains , and thus ICANN coordinates the technical aspects of the Internet, but without the right to set binding. ICANN was under 30 September 2009 the Department of Commerce (Department of Commerce) of the United States and thus the U.S. government . Since October 1, 2009 and replaces a joint “declaration of binding agreements” (Affirmation of commitment) the previous agreement (Joint Project Agreement, JPA), which representatives of governments and interested stakeholders should regularly assess whether the ICANN organization to fulfill its responsibilities in accordance with statutory .

ICANN is sometimes used as a sort of world government of the Internet means. The governments of the world are in the Governmental Advisory Committee ( Governmental Advisory Committee , GAC) represented the independent seat at the EU Commission in Brussels has one. As the headquarters of the organization even after 1 2009 in the U.S. remains October, network management organization is subject to the continuing American jurisprudence.

Formation

ICANN was in October 1998 a coalition of various interest groups (business, technology, science and users) founded by. Legally, it is in ICANN is a private foundation based in Marina del Rey, California. The ICANN is responsible for a number of technical requirements, previously of the IANA and various other groups were taken, focusing on.

Objects of the work of ICANN

In order for the Internet, certain names and addresses are globally unique. Therefore, ICANN coordinates:

• on the Address Supporting Organization and the Country Code Names Supporting Organization (ccNSO), the Internet domain name ( domain name system , especially the DNS root name server )
• the IP addresses ,
• in cooperation with the IETF protocol parameters and port addresses of the Internet protocol suite .

Organization

The Board of Directors of ICANN is composed of 21 members from around the world. 15 members have voting rights: to be a night Nominierungskommittee elected, two by the Address Supporting Organization (ASO), two of the country-code Name Supporting Organization (ccNSO) and two of the Generic Name Supporting Organization (GNSO), which coincides CEO . Six non-voting members are nominated by advisory organizations. 2000 members, five representing the user base of a continent selected public, with the expiration of their time member of the 2003 public election, however, abolished.

Chairman of the board is Peter Dengate Thrush. President & CEO of ICANN since 2009 July is Rod Beckstrom, chief operating officer since September 2010 Akram Atallah. Board members were from Germany until 2003 Helmut Schink ( Siemens AG ) and the journalist Andy Mueller-Maguhn (Deputy Chairman of the Chaos Computer Club Berlin e. V.), the representative was elected as European. Another member from Germany until 2006 Hultzsch Hagen (a former board member of the German Telekom AG ). Karl Auerbach , the public representatives of the North American user base 2000 to 2003, sat down for more openness and transparency of ICANN for a. In 2002, he complained before a Superior Court in California successfully for access to the books.

Alternative root server

An alternative to the ICANN root servers to the OpenNIC Project is . To 31 December 2008 formed the Open Root Server Network (Ørsnes), which partially IPv6 was enabled, an alternative to the ICANN root servers

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