TCP/IP and DNS

1,793 views

Published on

Published in: Education

TCP/IP and DNS

  1. 1. SEMINAR ON TCP/IP AND DNSBy Biswadip Dey (Roll No. – 11G5MMS136)
  2. 2. 1/1/2013 6:33 AMCONTENTS WHAT IS TCP/IP ARCHITECTURE OF TCP/IP HOW TCP/IP WORKS DIFFERENCE BETWEEN TCP/IP AND OSI WHAT IS DNS DOMAIN NAME SPACE DNS SERVERS AND DIFFERENT TYPES OF DNS SERVERS TYPES OF DNS RESOLVER AND RESOLUTION TECHINQUES REFERENCES 2
  3. 3. 1/1/2013 6:33 AMWHAT IS TCP/IP? TCP/IP is named after its two primary protocol TCP and IP. TCP/IP stands for Transmission Control Protocol / Internet Protocol. TCP/IP defines how electronic devices (like computers) should be connected to each other, and how data should be transmitted between them. 3
  4. 4. 1/1/2013 6:33 AMARCHITECTURE OF TCP/IP OSI MODEL Application TELNE Presentation DNS SMTP FTP HTTP … Application T Session Transport SCTP TCP UDP Transport ICMP IGMP Network IP Internet RARP ARP Data Link Physical 4
  5. 5. 1/1/2013 6:33 AMPHYSICAL LAYER The physical layer is responsible for moving individual bits between two hops or node. It defines Transmission Rate (the number of bits sent each second). It is responsible for synchronization of bits. The physical layer is also concerned with the physical topology. 5
  6. 6. 1/1/2013 6:33 AMARCHITECTURE OF TCP/IP OSI MODEL Application TELNE Presentation DNS SMTP FTP HTTP … Application T Session Transport SCTP TCP UDP Transport ICMP IGMP Network IP Internet RARP ARP Data Link Physical 4
  7. 7. 1/1/2013 6:33 AMDATA LINK LAYER The data link layer is responsible for error control and flow control. Here the unit of communication is a frame. The header of frame contains source address and destination address along with other information. The trailer of frame is used to achieve error control mechanism. 6
  8. 8. 1/1/2013 6:33 AMARCHITECTURE OF TCP/IP OSI MODEL Application TELNE Presentation DNS SMTP FTP HTTP … Application T Session Transport SCTP TCP UDP Transport ICMP IGMP Network IP RAR Internet ARP P Data Link Physical 4
  9. 9. 1/1/2013 6:33 AMINTERNET LAYER At the Internet layer, TCP/IP supports the Internet Protocol (IP). IP transports data in packets called datagrams. Datagrams can travel along different routes. IP does not keep track of the routes and has no facility for reordering datagrams once they arrive at their destination. Communication at the internet layer is end- to-end. 7
  10. 10. 1/1/2013 6:33 AMINTERNET LAYER (CONTINUES…) ARP (Address Resolution Protocol) is used to associate a logical address to its corresponding physical address. RARP (Reverse Address Resolution Protocol) allows a host to discover its logical address when it knows only its physical address. ICMP (Internet Control Message Protocol) is used by hosts and gateways to send notification of datagram problems, back to the sender. IGMP (Internet Group Message Protocol) is used to facilitate the simultaneous transmission of message to a group of recipients. 8
  11. 11. 1/1/2013 6:33 AMARCHITECTURE OF TCP/IP OSI MODEL Application TELNE Presentation DNS SMTP FTP HTTP … Application T Session Transport SCTP TCP UDP Transport ICMP IGMP Network IP Internet RARP ARP Data Link Physical 4
  12. 12. 1/1/2013 6:33 AMTRANSPORT LAYER The transport layer is responsible for delivering the whole message (also called user datagram or segment) from source process to destination process. The communication at this layer is process-to- process. Transport layer defines three protocol namely UDP (User Datagram Protocol), TCP (Transmission Control Protocol) & SCTP (Stream Control Transmission Protocol) 9
  13. 13. 1/1/2013 6:33 AMTRANSPORT LAYER (CONTINUES…) UDP does not create any virtual connection between the source and destination processes, so it is a connectionless protocol. UDP does not support acknowledgement , so it is a unreliable protocol. UDP uses port numbers to create a process-to- process communication. UDP does provide error control to some extent. If UDP detects an error in the received packet, it silently drops it. UDP packets are called user datagrams. 10
  14. 14. 1/1/2013 6:33 AMTRANSPORT LAYER (CONTINUES…) TCP creates a virtual connection before sending packet, so it is connection oriented protocol. TCP supports acknowledgement, so it is a reliable protocol. TCP uses port numbers to provides process- to-process communication. TCP is a stream-oriented protocol. A packet in TCP is called a segment. 11
  15. 15. 1/1/2013 6:33 AMTRANSPORT LAYER (CONTINUES…) SCTP combines the best features of UDP and TCP. SCTP is a reliable message oriented protocol. It preserves the message boundaries and at the same time detects lost data, duplicate data, and out-of-order data. It also has congestion control and flow control mechanisms. 12
  16. 16. 1/1/2013 6:33 AMARCHITECTURE OF TCP/IP OSI MODEL Application TELN Presentation DNS SMTP FTP HTTP … Application ET Session Transport SCTP TCP UDP Transport ICMP IGMP Network IP Internet RARP ARP Data Link Physical 4
  17. 17. 1/1/2013 6:33 AMAPPLICATION LAYER The application layer in TCP/IP is equivalent to the combined session, presentation, and application layers in the OSI model. The application layer allows a user to access the services of our private internet or the global Internet. Many protocols are defined at this layer to provide services such as electronic mail, file transfer, accessing the World Wide Web, and so on. 13
  18. 18. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 Message P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  19. 19. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer H Message Application Layer Connec Transport Layer 1,58,53 t 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  20. 20. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Connec Internet Layer 1,2 1,58,53 t Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  21. 21. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Connec Data-link Layer 41,45 1,2 1,58,53 t T Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  22. 22. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Connec Physical Layer H 41,45 1,2 1,58,53 t T Physical Layer R1 R3 R2 14
  23. 23. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Connec Physical Layer H 46,47 1,2 1,58,53 t T Physical Layer R1 R3 R2 14
  24. 24. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Connec Physical Layer 46,47 1,2 1,58,53 t T Physical Layer R1 R3 R2 14
  25. 25. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Connec Data-link Layer 1,2 1,58,53 t Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  26. 26. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Connec Internet Layer 1,58,53 t Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  27. 27. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage 2,53,58 Ack Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  28. 28. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  29. 29. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 2,58,53 H Mes 3,58,53 2,58,53sage Mes H 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  30. 30. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Application Layer Transport Layer 4,58,53 Close 2,58,53 H Mes 3,58,53 sage Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  31. 31. 1/1/2013 6:33 AMPUTTING ALL TOGETHER P2 P3 P1 P1 P5 P6 99 66 58 53 46 23Source Destinatio n Application Layer Message Application Layer Transport Layer H Message Transport Layer Internet Layer Internet Layer Data-link Layer Data-link Layer Physical Layer Physical Layer R1 R3 R2 14
  32. 32. 1/1/2013 6:33 AMCOMPARISONS BETWEEN TCP/IP AND OSI When we compare the two models, we find that two layers, session and presentation, are missing from the TCP/IP protocol suite. The OSI Model specifies which function belongs to each of its layers. Whereas TCP/IP defines protocols for each layer which provides a specific functionality, the protocols are not necessarily interdependent. 15
  33. 33. 1/1/2013 6:33 AMWHAT IS DNS? Domain Name System (DNS) is a hierarchical distributed database system that translates a computers fully qualified domain name into an IP address or vise versa. 16
  34. 34. 1/1/2013 6:33 AMDOMAIN NAME SPACE It is a hierarchical name space. It is an inverted-tree structure with root at the top. Each node in the tree has a label, which is a string with a maximum of 63 characters. The root is labeled by null string (.). Children of each node have unique labels. A domain name is a sequence of labels separated by dots (.). 17
  35. 35. 1/1/2013 6:33 AMDOMAIN NAME SPACE (CONTINUES…) If a sequence of labels is terminated by a null string (.), it is called a fully qualified domain name (FQDN). If a sequence of labels is not terminated by a null string, it is called a partially qualified domain name (PQDN). 18
  36. 36. 1/1/2013 6:33 AMDOMAIN NAME SPACE (CONTINUES…) A domain is a subtree of the domain name space. The name of the domain is the name of the node at the top of the subtree. 19
  37. 37. 1/1/2013 6:33 AMDNS SERVERS This are the servers which stores the information about its domain and subdomains. Each server is responsible for keeping the information about its domain and subdomains. The undertaking domain and subdomains forms a zone. Each DNS servers maintains a database known as zone file to keep the information about its zone. 20
  38. 38. 1/1/2013 6:33 AMDIFFERENT TYPES OF DNS SERVERS Root Server Primary DNS Server Secondary DNS Server Cache Only DNS Server 21
  39. 39. 1/1/2013 6:33 AMROOT SERVER A root server is a server whose zone consists of all the other DNS servers. The root server does not keep information about its undertaking DNS servers. It rather keeps a reference to the those DNS servers. 22
  40. 40. 1/1/2013 6:33 AMPRIMARY DNS SERVER A Primary DNS Server is a server that stores a file about the zone for which it is an authority. It is responsible for creating, maintaining, and updating the zone file. It stores the zone file on a local disk. 23
  41. 41. 1/1/2013 6:33 AMSECONDARY DNS SERVER A Secondary DNS Server is a server that gathers the complete information (zone file) about a zone from another server (primary or secondary) and stores the file on its local disk. The secondary server neither creates nor updates the zone files. If updating is required, it must be done by the Primary DNS Server, which sends the updated version to the Secondary DNS server. 24
  42. 42. 1/1/2013 6:33 AMPURPOSE OF PRIMARY & SECONDARY DNS SERVER Zone Zone File File Secondary Primary DNS Server DNS Server 25
  43. 43. 1/1/2013 6:33 AMCACHE ONLY DNS SERVER To speed up the resolution this server is used. It caches the mapping information before sending the response to the client. If the same or another client ask for the same mapping then it resolve the problem by itself rather going to the authoritative source. It uses a TTL (Time-To-Live) to validate the mapping. 26
  44. 44. 1/1/2013 6:33 AMWORKING PRINCIPAL OF CACHE ONLY DNS SERVER Authoritative DNS Server Cache Only INFORMATIO INFORMATIO DNS Server N N 27
  45. 45. 1/1/2013 6:33 AMTYPES OF DNS In the Internet, the domain name space (tree) is divided into three different sections: generic domains, country domains, and the inverse domain. 28
  46. 46. 1/1/2013 6:33 AMGENERIC DOMAIN The generic domains define registered hosts according to their generic behavior. 29
  47. 47. 1/1/2013 6:33 AMCOUNTRY DOMAIN The country domains section uses two- character country abbreviations. 30
  48. 48. 1/1/2013 6:33 AMINVERSE DOMAIN The inverse domain is used to map an address to a name. 31
  49. 49. 1/1/2013 6:33 AMWHAT IS RESOLVER Resolver is a DNS client. It gets the request from its host’s processes and searches its nearest DNS server. After getting the response from server it transfers the result to the host’s process that requested it. 32
  50. 50. 1/1/2013 6:33 AMRESOLUTION Mapping a name to an address or an address to a name is called name-address resolution. There are two types of resolutions techniques, Recursive Resolution and Iterative Resolution. 33
  51. 51. 1/1/2013 6:33 AMRECURSIVE RESOLUTION root server edu com exam.ed u yahoo.com ClientRequests: yahoo.com 34
  52. 52. 1/1/2013 6:33 AMITERATIVE RESOLUTION root server edu com exam.ed u yahoo.com ClientRequests: yahoo.com 35
  53. 53. 1/1/2013 6:33 AMREFERENCES Data Communications and Networking (Fourth Edition) By Behrouz A Forouzan, Published by McGraw-Hill Computer Networks (Fourth Edition) By Andrew S. Tanenbaum, Published by Pearson Education TCP/IP Protocol Suite (Fourth Edition) By Behrouz A Forouzan, Published by McGraw- Hill 36

×