BZUPAGES.COM

BZUPAGES.COM

Presented to: Sir. Muizuddin sbPresented by:

M.Sheraz Anjum Roll NO.07-16Atif Aneaq Roll NO. 07-15Khurram Shehzad Roll NO. 07-32Wasif Laeq Roll NO. 07-01Taha Khan Roll NO. 07-06Bukhtyar Ali Roll NO. 07-18Hafiz Shahrukh Roll NO. 07-22Muhammad Arqum Roll NO. 06-24

Bs(IT) 6th

Department Of Information Technology

(Institute of Computing)B-Z-UB.Z.U

BZUPAGES.COM

Domain Name

• A domain name is an identification label that defines a scope of administrative autonomy, authority, or control in the Internet, based on the Domain Name System (DNS).

• Simply it is a user friendly name.

BZUPAGES.COM

Domain Name System

Definition:It is a hierarchical naming system for computers, services, or any resource connected to the Internet or a private network.

• Associates various information with domain names assigned to each of the participants.

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Explanation

• It translates domain names meaningful to humans into the numerical identifiers associated with networking equipment for the purpose of locating and addressing these devices worldwide.

• It serves as the "phone book" for the Internet by translating human-friendly computer hostnames into IP addresses.For example: www.bzupages.com translates to 69.162.70.115.

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Characteristics

• Domain names are assigned to groups of Internet users.

• It is independent of each user's physical location.

• Is easier to remember than IP addresses such as 208.77.188.166.

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An Intro To basic Authorities

• The Domain Name System distributes the responsibility of assigning domain names and mapping those names to IP addresses by designating authoritative name servers for each domain.

• Authoritative name servers are assigned to be responsible for their particular domains, and in turn can assign other authoritative name servers for their sub-domains.

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Domain name space

• Consists of a tree of domain names.

• Zone(Domain) consists of a collection of connected nodes, served by an authoritative name server.

• Single name server can host several zones.

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Domain name space (Cont.)

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Domain name space (Cont.)

• Administrative responsibility over any zone may be divided, thereby creating additional zones.

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Domain name formulation

• A domain name consists of one or more parts called labels .

• Labels are conventionally concatenated, by dots, such as IFhosting.com.

• The right-most label conveys the top-level domain

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Domain name formulation (Cont)

• Descends from right to left .

• Each label to the left specifies a subdivision, or sub domain of the domain to the right .

• E.g in www.ifhsoting.com

• Label ifhostingifhosting is sub domain of .com and wwwwww is the sub domain of ifhosting.com

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Domain name formulation (Cont)

• This tree of subdivisions may consist of 127 levels .

• Each label may contain up to 63 characters

• The full domain name may not exceed a total length of 253 characters.

thelongestlistofthelongeststuffatthelongestdomainnameatlonglast.com/

BZUPAGES.COM

Domain name formulation (Cont)

• The characters allowed in a label are a subset of the ASCII character set, and includes– a through z – A through Z – digits 0 through 9 – Hyphen

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Domain name formulation (Cont)

• Hostname: It is a domain name that has at least one IP address associated .

For example:

The domain names www.example.com and sheikho.com are hostnames.

Whereas .com is not a hostname.

BZUPAGES.COM

Types of Domains

• Generic Top Level Domain (GTLD)– E.g .com .org .net

• Country Code Top Level Domain (CCTLD)– E.g .pk .in .un

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Internationalized domain names

• Permitted character set of the DNS prevented the representation of names and words of many languages in their native alphabets.

• ICANN has approved the Punycode-based internationalized domain name (IDNA)

• system.– e.g محمد.com

• In 2009 ICANN approved the installation of IDN country code top-level domains.

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Name servers

• The Domain Name System is maintained by a distributed database system.

• The nodes of this database are the name servers.

• Each domain has at least one authoritative DNS server.

• The top of the hierarchy is served by the root name servers.

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Name servers (Cont.)

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Primary and Secondary NS

• Primary name server and secondary name servers are required.

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Recursive and caching name server

• Every DNS query must start with recursive queries at the root zone of the Domain Name System.

• The Domain Name System supports DNS cache servers which store DNS query results for a period of time.

• Many home networking routers implement DNS caches and improve efficiency in the local network.

BZUPAGES.COM

DNS resolvers

• The client-side of the DNS is called a DNS resolver.

• Initiates and sequences queries.

• A DNS query may be either a non-recursive query or a recursive query.

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• Address resolution mechanism

• Record caching

• Client lookup

• Other applications

Operation

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Address Resolution Mechanism

BZUPAGES.COM

Record Caching

• A mechanism to reduce the load on individual DNS servers.

• Records are cached for a period of time after an answer.

• Time to live (TTL) time for which a resolver caches a

DNS response.

• Changes to DNS records do not propagate throughout the network immediately

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Client lookup

• Users generally do not communicate directly with a DNS resolver.

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Other applications

• Hostnames and IP addresses do not necessarily match on a one-to-one basis.

• There are many uses of DNS besides translating names to IP addresses.

• E-mail Blacklists

• Software Updates ( e.g an AntiVirus)

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Other applications (Cont.)

• Multiple DNS servers are usually provided for coverage of all domains.

• Thirteen very powerful root servers exist to provide flexibility in case of computer failure.

• Dynamic DNS (also referred to as DDNS) provides clients the ability to update their IP address in the DNS.– As in case of DHCP, dynamically IP addresses are

assigned to users from pool of IP addresses.

BZUPAGES.COM

Domain name registration

• The right to use a domain name is given by domain name registrars.

– e.g dotcomgenie.com• It is credited by the Internet Corporation for Assigned

Names and Numbers (ICANN).• A registry is responsible for maintaining the database of

names registered within the Top Level Domain (TLD) it administers.

• The registry receives registration information from each domain name registrar authorized to assign names in the corresponding TLD.

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Domain name registration (Cont)

• The registry publishes this information using a special service, the WHOIS protocol.

• Some domain name registries, often called network information centers (NIC), also function as registrars to end-users.

• The registrants (users of a domain name) are customers of the registrar

BZUPAGES.COM

Domain Tools

www.whois.domaintools.com/

Store all NS and registration information abouteach WWW.

BZUPAGES.COM

BZUPAGES.COM