The document discusses the Domain Name System (DNS). It describes DNS as a hierarchical and distributed database that maps hostnames to IP addresses. DNS uses a tree structure with nodes containing domain names that are read from the node up to the root. The document outlines the key components of DNS including fully and partially qualified domain names, zones, primary and secondary name servers, and the different top-level domains like generic, country, and inverse domains used for name to address and address to name lookups.
A complete Coverage of DNS and its features. This ppt deals with well balanced practical and theoretical aspects of DNS. The best ppt for a novice learner.
Learn about the essentials of the Domain Name System (DNS), including name resolution, different record types, roots, zones, authority and recursion.
See the full webinar and the rest of the series at https://www.thousandeyes.com/resources/intro-to-dns-webinar
A complete Coverage of DNS and its features. This ppt deals with well balanced practical and theoretical aspects of DNS. The best ppt for a novice learner.
Learn about the essentials of the Domain Name System (DNS), including name resolution, different record types, roots, zones, authority and recursion.
See the full webinar and the rest of the series at https://www.thousandeyes.com/resources/intro-to-dns-webinar
Overview of the Domain Name System (DNS).
In the early days of the Internet, hosts had a fixed IP address.
Reaching a host required to know its numeric IP address.
With the growing number of hosts this scheme became quickly awkward and difficult to use.
DNS was introduced to give hosts human readable names that would be translated into a numeric IP addresses on the fly when a requesting host tried to reach another host.
To facilitate a distributed administration of the domain names, a hierarchic scheme was introduced where responsibility to manage domain names is delegated to organizations which can further delegate management of sub-domains.
Due to its importance in the operation of the Internet, domain name servers are usually operated redundantly. The databases of both servers are periodically synchronized.
This slide contains details about domain name servers (DNS).
It also contains Resolution of the Name Servers with Domain Name Structure with statistics table. The process of Name resolution is also explained with Recursive and iterative resolution processes.
Overview of UDP protocol.
UDP (User Datagram Protocol) is a simple extension of the Internet Protocol services. It basically provides simple packet transport service without any quality of service functions.
Unlike TCP, UDP is connection-less and packet-based. Application PDUs (application packets) sent over a UDP socket are delivered to the receiving host application as is without fragmentation.
UDP is mostly used by applications with simple request-response communication patterns like DNS, DHCP, RADIUS, RIP or RPC.
Since UDP does provide any error recovery such as retransmission of lost packets, the application protocols have to take care of these situations.
Overview of RARP, BOOTP, DHCP and PXE protocols for dynamic IP address assignment.
Dynamic IP address assignment to a host (or interface) is a common problem in TCP/IP based networks.
Manual and static assignment of IP addresses does not scale well and becomes a labor intensive task with a growing number of hosts.
An early approach for dynamic IP address assignment was RARP (Reverse ARP) which ran directly on the Ethernet protocol layer.
The many problems of RARP such as the inability to be routed between subnets were solved with BOOTP (Bootstrap Protocol).
BOOTP, however, ended to have its own set of limitations like lack of a lease time for IP addresses.
DHCP (Dynamic Host Configuration Protocol) was therefore defined as an extension to BOOTP.
DHCP is backward compatible with BOOTP thus allowing some degree of interoperability between the 2 protocols.
The state-of-the-art protocol for dynamic IP address assignment is, however, is DHCP.
DHCPv6 is an adaption of DHCP for IPv6 based networks.
DHCP Stands for Dynamic Host Configuration Protocol.
DHCP is a protocol that automatically provides an IP host with its IP address and other related configuration information ( subnet mask, default gateway,DNS etc. )
Works on Protocol UDP port no 67 and 68.
Overview of the Domain Name System (DNS).
In the early days of the Internet, hosts had a fixed IP address.
Reaching a host required to know its numeric IP address.
With the growing number of hosts this scheme became quickly awkward and difficult to use.
DNS was introduced to give hosts human readable names that would be translated into a numeric IP addresses on the fly when a requesting host tried to reach another host.
To facilitate a distributed administration of the domain names, a hierarchic scheme was introduced where responsibility to manage domain names is delegated to organizations which can further delegate management of sub-domains.
Due to its importance in the operation of the Internet, domain name servers are usually operated redundantly. The databases of both servers are periodically synchronized.
This slide contains details about domain name servers (DNS).
It also contains Resolution of the Name Servers with Domain Name Structure with statistics table. The process of Name resolution is also explained with Recursive and iterative resolution processes.
Overview of UDP protocol.
UDP (User Datagram Protocol) is a simple extension of the Internet Protocol services. It basically provides simple packet transport service without any quality of service functions.
Unlike TCP, UDP is connection-less and packet-based. Application PDUs (application packets) sent over a UDP socket are delivered to the receiving host application as is without fragmentation.
UDP is mostly used by applications with simple request-response communication patterns like DNS, DHCP, RADIUS, RIP or RPC.
Since UDP does provide any error recovery such as retransmission of lost packets, the application protocols have to take care of these situations.
Overview of RARP, BOOTP, DHCP and PXE protocols for dynamic IP address assignment.
Dynamic IP address assignment to a host (or interface) is a common problem in TCP/IP based networks.
Manual and static assignment of IP addresses does not scale well and becomes a labor intensive task with a growing number of hosts.
An early approach for dynamic IP address assignment was RARP (Reverse ARP) which ran directly on the Ethernet protocol layer.
The many problems of RARP such as the inability to be routed between subnets were solved with BOOTP (Bootstrap Protocol).
BOOTP, however, ended to have its own set of limitations like lack of a lease time for IP addresses.
DHCP (Dynamic Host Configuration Protocol) was therefore defined as an extension to BOOTP.
DHCP is backward compatible with BOOTP thus allowing some degree of interoperability between the 2 protocols.
The state-of-the-art protocol for dynamic IP address assignment is, however, is DHCP.
DHCPv6 is an adaption of DHCP for IPv6 based networks.
DHCP Stands for Dynamic Host Configuration Protocol.
DHCP is a protocol that automatically provides an IP host with its IP address and other related configuration information ( subnet mask, default gateway,DNS etc. )
Works on Protocol UDP port no 67 and 68.
A presentation on DNS concepts. It covers the topics DNS Introduction, DNS Hierarchy, DNS Resolution Process,
DNS Components, DNS Types, DNSSEC, DNS over TLS (DoT) & HTTPS (DoH), Oblivious DNS (ODoH).
The Domain Name System (DNS) is a hierarchical decentralized naming system that resolves Name to IP or vise versa.
DNS works with port no 53 (TCP and UDP )
For query resolving UDP protocol is used and for Zone transfer TCP port is used.
Acetabularia Information For Class 9 .docxvaibhavrinwa19
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The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
For more information, visit-www.vavaclasses.com
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
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The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
Welcome to TechSoup New Member Orientation and Q&A (May 2024).pdfTechSoup
In this webinar you will learn how your organization can access TechSoup's wide variety of product discount and donation programs. From hardware to software, we'll give you a tour of the tools available to help your nonprofit with productivity, collaboration, financial management, donor tracking, security, and more.
Operation “Blue Star” is the only event in the history of Independent India where the state went into war with its own people. Even after about 40 years it is not clear if it was culmination of states anger over people of the region, a political game of power or start of dictatorial chapter in the democratic setup.
The people of Punjab felt alienated from main stream due to denial of their just demands during a long democratic struggle since independence. As it happen all over the word, it led to militant struggle with great loss of lives of military, police and civilian personnel. Killing of Indira Gandhi and massacre of innocent Sikhs in Delhi and other India cities was also associated with this movement.
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
2. DNS- Definition
Name Space
◦ Flat Name Space
◦ Hierarchical Name Space
Domain Name Space
◦ FULLY QUALIFIED DOMAIN NAME(FQDN)
◦ PARTIALLY QUALIFIED DOMAIN NAME(PQDN)
Distribution of Name Space
◦ Hierarchy of Name servers
◦ Zone and Domains
◦ Root, Primary and Secondary Servers
DNS in Internet
◦ Generic , Country and Inverse Domain
Resolution
DNS messages
DNS By Diwaker Pant October 9, 2012 2
3. To identify an entity, TCP/IP uses IP addresses which
uniquely identifies connection of host to internet.
We prefer to use names instead of numeric addresses .
So we need a system that can map a name to a numeric
address and vice versa. This is called DOMAIN NAME
SYSTEM
DNS By Diwaker Pant October 9, 2012 3
4. When internet was small, mapping was done using
HOST FILE which was stored on every host.
Host file had only two columns: name and address.
But now a days whole information is divided into
smaller parts and each part is stored in different
computer. This is called DNS.
DNS By Diwaker Pant October 9, 2012 4
5. The process of mapping a unique name with the unique
IP address.
FLAT NAME SPACE –
A name is assigned to an address and name is a
sequence of characters without structure.
It can not be used in large system such as Internet.
DNS By Diwaker Pant October 9, 2012 5
6. HIERARCHICAL NAME SPACE-
Each name is made of several parts.
The first part can define the nature of organization.
Second part can define the name and third can define
the departments in organization.
For example
o Smart.pu.edu
o Smart.nitttr.edu
o smart.unix.com
DNS By Diwaker Pant October 9, 2012 6
7. To have a hierarchical name space, a DOMAIN NAME
SPACE was designed.
In this design the names are defined in an inverted tree
structure with the root at top.
The tree can have only 128 levels i.e. level 0(root) to
level 127.
Tree consists of nodes and each node has a LABEL.
DNS By Diwaker Pant October 9, 2012 7
8. Label is a string with a max. of 63 characters.
The root label is a null string.
Siblings have different labels to maintain uniqueness.
DNS By Diwaker Pant October 9, 2012 8
9. Each node in the tree has a domain name.
Full domain name is sequence of labels separated by
dots(.)
Domain name is read from node up to root.
Always ends in a null label i.e. last character is a dot.
DNS By Diwaker Pant October 9, 2012 9
11. FULLY QUALIFIED DOMAIN NAME(FQDN)
It contains the full name of host.
A label is terminated by a null string.
PARTIALLY QUALIFIED DOMAIN NAME(PQDN)
It starts from a node but doesn’t reaches root.
A label is not terminated by null string.
October 9, 2012 DNS By Diwaker Pant 11
12. Domain is a sub
tree of domain
name space.
Each domain can
be divided into
sub domains.
October 9, 2012 DNS By Diwaker Pant 12
14. Region over which server
has the responsibility and
authority.
Zone is a part of entire
tree.
Server can divide domain
into smaller domains.
October 9, 2012 DNS By Diwaker Pant 14
15. ROOT SERVER-It is a server whose zone consist of
whole tree. These servers are distributed all around the
world.
PRIMARY SERVER- A primary server loads all
information from the local disk file.
SECONDARY SERVER- It transfer the complete
information from the primary server and it is called
Zone transfer.
DNS By Diwaker Pant October 9, 2012 15
16. DNS is a protocol can be used in different platforms.
In the internet, DNS tree is divided into three different sections
DNS By Diwaker Pant October 9, 2012 16
17. It contains registered hosts according to generic behaviors.
October 9, 2012 DNS By Diwaker Pant 17
18. Label Description
com Commercial organizations
edu Educational institutions
gov Government institutions
int International organizations
mil Military groups
net Network support centers
org Nonprofit organizations
October 9, 2012 DNS By Diwaker Pant 18
19. Label Description
aero Airlines and aerospace companies
biz Businesses or firms (similar to com)
coop Cooperative business organizations
info Information service providers
museum Museums and other nonprofit organizations
name Personal names (individuals)
pro Professional individual organizations
October 9, 2012 DNS By Diwaker Pant 19
21. Use to map an address to a
name.
When a server received a
request from a client to do a
task.
Inverse or pointer (PTR)
query.
121.45.34.132.in-addr.arpa
October 9, 2012 DNS By Diwaker Pant 21
22. Mapping a name to an address or an address to a name is
called name –address resolution.
RESOLVER-It access the closest DNS server with a
mapping request. If the server has the information, it
satisfies the resolver ; otherwise refers the resolver to
other servers or asks the other servers to provide the
information.
MAPPING NAMES TO ADDRESSES-
Resolver gives domain name to the server and ask for
address. It uses country and generic domain to find the
mapping.
DNS By Diwaker Pant October 9, 2012 22
23. MAPPING ADDRESS TO NAMES.
Resolver sends IP address to the server to be mapped
to domain name.
This is called PTR or Inverse query.
Server uses inverse domain.
IP address -121.45.34.132
Domain name-132.34.45.121.in-addr.arpa.
DNS By Diwaker Pant October 9, 2012 23
25. ITERATIVE RESOLUTION
DNS By Diwaker Pant October 9, 2012 25
26. CACHING
When a server asks for mapping from another server and
receive the response, it stores the information an its cache
memory before sending it to the clients.
If the same or other client ask for the same mapping, it can
check its cache memory and resolve the problem.
But this type of response is always marked as
unauthoritative.
DNS By Diwaker Pant October 9, 2012 26
27. Query and response
DNS By Diwaker Pant October 9, 2012 27
29. In DNS , when there is a change , such as adding a new
host, removing a host or changing an IP address,
change must be made to the DNS master file.
Manual updating is not possible due to size of Internet.
It is use to update DNS master file automatically.
Information in both primary and secondary servers is
changed.
DNS By Diwaker Pant October 9, 2012 29
30. DNS can use either UDP or TCP.
PORT NO. 53 is used by servers.
If size of response message is more than 512 bytes,
TCP connection is used, otherwise UDP is used.
How are the new domains added to the server.
DNS By Diwaker Pant October 9, 2012 30
31. This is done through a registrar, a commercial entity
accredited by ICANN (Internet corporation for
assigned name and numbers).
Name is added to the DNS database after verification
by Registrar for uniqueness of the name.
A fee is charged.
DNS By Diwaker Pant October 9, 2012 31
32. The domain name system is a client /server application
that identifies each host on the internet with a unique
friendly name.
Its structure is an inverted hierarchical tree structure.
Each node in the tree has a domain name.
Generic domain , Country domain, Inverse domain.
DDNS automatically updates the DNS master.
DNS use the service UDP for message of less than 512
bytes .otherwise, TCP is used.
DNS By Diwaker Pant October 9, 2012 32
33. Behrouz A. Forouzan - Data Communication and
Networking (3rd ,4th edition)
Andrew S. Tanenbaum - Computer Networks (4th
edition)
DNS By Diwaker Pant October 9, 2012 33
35. The client (resolver) can ask for the answer from a name server,
generally closet DN server.
If the server is the authority for the domain name it will responds
back with the full answer after checking its database, but if the closet
server is not the authority then it will pass query to next closet server
generally parent.
Then this server will again check its database and responds back with
answer if it is authority, otherwise it will pass the query to next
server…
This process will repeats until the authoritative server gives final
answer.
When the query is finally resolved. The response travels back to
requesting client.
DNS By Diwaker Pant October 9, 2012 35
36. If the clients does not ask for the recursive answer, the mapping can
be done iteratively.
If the server is an authority for the name, it sends the answer.
If it is not then it returns (to the clients) the IP add of the server that it
thinks can resolve the problem.
The client is responsible for repeating the query to new server.
If this new server can resolve the query then it will responds back
with the Final IP address as an answer otherwise it returns the IP
address of the new server.
This process is called Iterative because The client repeats the query to
multiple servers.
DNS By Diwaker Pant October 9, 2012 36
Editor's Notes
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 rd edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition) The client (resolver) can ask for the answer from a name server, generally closet DN server. If the server is the authority for the domain name it will responds back with the full answer after checking its database, but if the closet server is not the authority then it will pass query to next closet server generally parent. Then this server will again check its database and responds back with answer if it is authority, otherwise it will pass the query to next server… This process will repeats until the authoritative server gives final answer. When the query is finally resolved. The response travels back to requesting client.
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)
Behrouz A. Forouzan - Data Communication and Networking (3 rd ,4 th edition)