Computer networks allow computers to be connected and share resources. There are several types of networks including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). Networks can have different topologies like star, ring, bus, or hybrid and can be configured in a client-server, peer-to-peer, or hybrid model. Security is important for networks and involves measures like access control, encryption, firewalls, and monitoring to prevent unauthorized access or data breaches.

1. COMPUTER NETWORKS

2. PREVIEW What is Networking. Imp Terms. Types of Networks. LAN/MAN/WAN Topologies.

3. COMPUTER NETWORK A COLLECTION OF CMPTRS INTER-CONNECTED WITH THE HELP OF A MEDIA (WIRE,OFC,SATL etc..) IN SUCH A WAY THAT EXCHANGE OF DATA/INFO TAKES PLACE.

4. ADVANTAGES OF NETWORKING COMN RELATIVE PRICE OF CMPTRS VS COMN. SHARING OF INFO SHARING OF RESOURCES SHARING OF APPLNS/PGMES HIGH RELIABILITY. IMPROVED COMNS (MAILING). WEB SERVICES. DATA SERVICES AND MAINT CENTRALIZED

5. IMP TERMS Bandwidth . The amount of data that can be transmitted in a fixed amount of time. Broadband . A type of data transmission in which a single medium (wire) can carry several channels at once. Cable TV, for example, uses broadband transmission.

6. IMP TERMS Domain . A gp of networked computer that share a single Security Accounts Manager (SAM). Fiber Optic . A type of network cable that uses a central glass or plastic core surrounded by a plastic coating.

7. Protocol . A predefined set of rules that dictates how cmptrs or devices communicate and exchange data on the network. Firewall . A combination of hardware and software that protect a network from attack by hackers that could gain access through public networks, incl the Internet. IMP TERMS

8. Gateway . The hardware and software needed to connect two separate network environment so that comn can occur. TCP/IP (Txn Control Protocol/Internet Protocol) Address An address used by the Internet Protocol that identifies the device's loc on the network. IMP TERMS

9. Ping. A TCP/IP utility used to test whether another host is reachable. An request is sent to the host, who responds with a reply if it is reachable. The request timed out if the host is not reachable. Server. A computer that provides resources to the clients on the network. IMP TERMS

10. TYPES OF NETWORKS SERVER BASED (SERVER TO CLIENT) Contain clients and the servers that support them. PEER TO PEER Has no server and uses the network to share resources among indep peers. HYBRID NETWORK . A client–server network that also has peers sharing resources. Most net works are actually hybrid networks .

11. WINDOWS NETWORK OS Windows NT(New Technology) Windows 2000 Server Windows 2000 Advanced Server Windows 2003 Server (Standard, Enterprise Editions)

12. CLIENT-SERVER FILE SERVER CLIENTS NETWK OS IN FILE SERVER. CLIENTS HAVE THEIR OWN OS. CENTRALISED SERVICES—SECURITY,AND etc..

13. CLIENT-SERVER Advantages Strong central security. Central file storage. Eqpt sharing. Dedicated, faster than peer to peer Easy manageability of large No of cmptrs. Disadvantage Expensive Dedicated Hardware. Expensive network operating system and client license. A dedicated network administrator reqd.

14. PEER TO PEER NO NETWK OS. EACH MACHINE HAS OS. INDEP MACHINES PHYSICALLY CONNECTED TO EACH OTHER. RESOURCES ARE SHARED AMONG EQUALS. NO CENTRAL CONTROLLING AUTH. ALL MACHINES HAVE EQUAL RIGHTS. GIVES SHARE LEVEL SECURITY.

15. PEER TO PEER Advantages No extra investment in server HW and SW reqd. Easy setup. No network Admin reqd. Lower cost for small network. Sharing allowed. Disadvantages Inability of peers to handle many NW connections as servers. No central pt for file storing. Admin for all cmptrs. Weak security. Lack of management which makes large peer networks hard to work.

16. HYBRID NETWORKS Advantages Advantages of server based networking . Many of the advantages of peer based NW. Ability of users and network administrators to control security based on the imp of the shared resources. Disadvantage Hybrid computing shares the disadvantages of server based NW. Expensive Dedicated Hardware. Expensive network operating system and client license. A dedicated network administrator reqd.

17. NETWORK COMPUTERS CAN ALSO SHARE FAX MODEM. SCANNERS. HDD. FDD. CD-ROMS/DVD. PLOTTERS.

18. APPLICATIONS OF NETWORKING E MAIL E CHAT VIDEO CONFERENCE FILE TFR INTERNET

19. PRE-REQUISITES CONNECTIVITY (HW) SW

20. TYPES OF CMPTR NETWKS BASED ON TRANSMISSION TECHNOLOGY BROADCAST NETWORKS PT-TO-PT NETWORKS

21. BROADCAST NETWORKS SINGLE COMN CH SHARED BY ALL CMPTRS ON NW. PACKETS SEND BY ONE CMPTR RECEIVED BY ALL OTHERS. ADDRESS FD IN PACKET- SPECIFIES FOR WHOM INTENDED. PACKET CAN ALSO BE ADDRESSED TO ALL CMPTRS (BROADCAST).

22. PT TO PT NETWORKS MANY CONNECTIONS BETWEEN INDL PAIRS OF CMPTRS. PACKETS VISIT ONE OR MORE INTERMEDIATE MACHINES. MULTIPLE ROUTES . SMALLER NETWORKS – BROADCAST LARGER NETWORKS – PT TO PT

23. TYPES OF COMPUTER NETWKS BASED ON GEOGRAPHICAL SPREAD LAN MAN WAN INTERNET

24. LOCAL AREA NETWORKS PRIVATELY OWNED. WITHIN SAME BLDG/ CAMPUS – UPTO A FEW KMs. SPEED 10/100/1000 Mbps. NORMALLY BROADCAST TYPE / SWITCHED - STATIC, DYNAMIC TRANSMISSION TECHNOLOGY - SINGLE CABLE. TOPOLOGY (BUS , RING) SIMPLE NETWORK MGT

25. METROPOLITAN AREA NETWORKS BIGGER VERSION OF LAN. USES SIMILAR TECH AS LAN. MAY COVER A CITY. CAN BE PRIVATELY OWNED OR PUBLIC. NO SWITCHING ELEMENTS (SIMPLE DESIGN).

26. WIDE AREA NETWORKS SPANS LARGER GEOGRAPHICAL AREA. COLLECTION OF CMPTRS RUNNING APPLICATION PROGRAMS (HOSTS). SUBNET - CARRY MSGS FROM HOST TO HOST. SWITCHING ELEMENTS (ROUTERS). PACKET SENT FROM ROUTER TO ROUTER. (STORE AND FWD / PT TO PT) PT TO PT TOPOLOGIES

27. INTER-NETWORKS CONNECTING DIFFERENT NETWORKS WITH DIFFERING TOPOLOGIES / INCOMPATIBILITIES CONNECTED THROUGH GATEWAYS

28. WIRELESS NETWORKS LOW SPEEDS 1-2 Mbps HIGH ERROR RATES LIABLE TO INTERFERENCE

29. LAN TOPOLOGIES TOPOLOGY THE GEOMETRIC ARRANGEMENT OF DEVICES IN A NETWORK. TYPES OF TOPOLOGIES STAR TOPOLOGY RING TOPOLOGY BUS TOPOLOGY HYBRID TOPOLOGY

30. LAN – STAR TOPOLOGY

31. LAN – RING TOPOLOGY

32. LAN – BUS TOPOLOGY

33. LAN – HYBRID TOPOLOGY

34. DESIGNING: UNIT LEVEL LAN

35. DESIGN OF A LAN NETWORK PLG – NO OF CLIENTS, FUTURE GROWTH, NW COMPONENTS, NO OF SERVERS, TYPE OF CABLING. NETWORK DESIGN – LOC OF SERVERS, TOPOLOGY, PHYSICAL LAYOUT, SOFTWARE USAGE ETC. BOTTOM LINE; MAKE A BLUE PRINT . IMPLEMENTATION AND FINE TUNING. PHYSICAL AUDIT – TYPE OF MACHINE, REGD NOS, HARDWARE USERS, OS INSTALLED WITH VER, CD OF OS & OTHER APPLICATIONS. Contd…

36. DESIGNATE SYS ADMINISTRATOR. KEEP RECORD OF – SERVER CONFIG NIC CONFIG TCP/IP ADDRESS USER NAMES & PASSWORDS EMAIL CLIENT CONFIG NW SERVICES (PRINTERS, FILE SHARING, PERMISSIONS ETC)

37. SUGGESTED LAYOUT OF UNIT LAN SERVER ADJT QM 2IC CO DOCU CELL PAY & ALLCES CELL D COY A COY B COY C COY G BR PRI Q BR A BR

38. CYBER SECURITY

39. INFO SECURITY

40. GUIDING PRINCIPLE Cyber Security in Army is based on the guiding principle that the person who is generating info is also resp for its security.

41. INFO ASSETS Hardware Software Documentation Information

42. MOST SECURITY BREACHES OCCUR DUE TO : - POOR PASSWORD MGMT. NON ACCTG OF REMOVABLE MAGNETIC MEDIA. STORING OF CLASSIFIED INFO ON CMPTR HDD. POOR NETWORK ADMIN. UNACCTD COPYING OF DATA ON REMOVABLE MEDIA WEAK AUTHENTICATION PROCEDURES & ACCESS CONTROL. VULNERABILITY OF OP SYS & COTS SOFTWARE. ABSENCE OF ADEQUATE TOOLS & STD FOR DATA ENCRYPTION CAUSES OF SECURITY BREACHES

44. LIKELY BREACHES PERSONAL SECURITY PHYSICAL SECURITY HARDWARE SECURITY SOFTWARE SECURITY DATABASE SECURITY

45. PERSONAL SECURITY ALLOW ACCESS TO ONLY AUTH & TRAINED PERS. TRG CAPSULES. RECORD OF PERS WITH ACCESS TO CMPTR. SURPRISE CHECKS.

47. PHYSICAL SECURITY OLD FASHIONED LOCK & KEY. EACH CMPTR, PRINTER, PERIPHERAL IS RESP OF INDL OFFR/OR/CLK. RESTRICT ENTRY TO AUTH PERS. PASSWORD PROTECTION FOR ALL CMPTRS. SCREEN SAVER PASSWORD. FIRE PROTECTION.

48. HARDWARE SECURITY (Protection against crashes/breakdown) LOGICAL PARTITIONS. BACKUP DATA (PC/SERVERS) HOT STANDBY SERVERS STABILISED POWER SUP. ACCTG OF SECONDARY STORAGE MEDIA. ELECTRIC EARTHING. LIGHTENING PROTECTION. STRONG CABLING IN CONDUITS. PERIPHERAL ACCOUNTABILITY BY NAME. FAX. LOCK/UNLOCK CODES. PHOTOCOPY RECORD.

50. SOFTWARE SECURITY ONLY LICENSED SW. LATEST SOFTWARE PATCHES. REVIEW DEFAULT SETTING OF SOFTWARE.

52. DATABASE SECURITY DATA HIGHER THAN RESTD’ NOT TO BE HOSTED ON SERVER. SERVER / NAS PASSWORD - SYS ADMIN. SYS ADMIN TO DEFINE ACCESS CONTROL LISTS, ACCESS RIGHTS. CLIENT PC DATA - USER RESP. BACKUP.

53. MGMT OF REMOVABLE MEDIA EXTERNAL MARKING. LOCK & KEY. INCOMING /OUTGOING MEDIA TO BE AUTH BY AN OFFR. PHYSICAL CHECK OF MEDIA – ONCE A QTR. USE OF USB / FLASH MEDIA IS PROHIBITED, ?? LAPTOP/PDA. WILL NOT BE TAKEN HOME. SINCE USED FOR OFFICIAL WK, WILL NOT BE CONNECTED TO INTERNET.

54. NETWORK SECURITY IP addresses. Remote Login. Perimeter Defence.

55. PROCEDURAL SECURITY MSR LAN / SYS ADMINISTRATOR. SECURITY ADMINISTRATOR. NETWORK DOCUMENTATION. DATA BACKUPS. PVT SOFTWARE. CHOOSING EFFECTIVE PASSWORDS .

57. SECURITY OF CL DOCU Top Secret/Secret/Confd docu . Holding in Electronic from. Typing. Txn. Restd/Unclas Docu. Storage Reproduction & issue Txn (LAN is unclas ??)

59. SECURITY WHILE USING ARMY INTERNET DIAL UP ACCESS NOT PERMITTED. ONLY UNCLAS INFO TO BE TRANSMITTED.

60. NEVER CONNECT THE INTERNET PC TO YOUR OFFICE LAN OR ARMY INTRANET

61. SECURITY MSR WHILE USING INTERNET ONLY STAND ALONE PC TO BE USED. HDD NOT TO HAVE OFFICIAL DATA. ACCESS TO INTERNET ONLY ON NEED BASIS. LATEST AV SOFTWARE, CHECK ALL DOWNLOADS FOR VIRUSES. FIREWALL PROTECTED. IN CYBER LABS, PLACE PC BEHIND PROXY SERVER & FIREWALL. Contd/-

62. PERIPHERALS ON INTERNET NOT TO BE SHARED FOR OFFICIAL WK. MAINT USAGE REGISTER IN INTERNET LAB. BIOS, USER, SCREEN SERVER PASSWORD. AVOID ENTICING SITES. PCS AT HOME BEING USED FOR INTERNET - NO OFFICIAL DATA ON HDD. DO NOT SURF THE NET ON AN ADMIN ACCT.

63. VIRUS PROTECTION REGULAR CHECK OF HDD. USE ONLY LEGAL SOFTWARE. RUN AV SOFTWARE WHEN OPENING ANY FILE.

65. REPAIR & MAINT AS FAR AS POSSIBLE, IN-SITU REPAIRS. STN WKSP RESP FOR REPAIRS AFTER WARRANTY. REMOVE HDD BEFORE SENDING TO WKSP. REPAIR THROUGH CIV FIRM DURING WARRANTY. IN SITU, PHYSICAL PRESENCE OF PERS DURING REPAIRS. IF SYS TO BE MOVED OUT, REMOVE HDD. UNREPAIRABLE HDD, GET CERTIFIED AS BER. PHYSICAL DESTRUCTION.

66. THANK YOU