1 / 56

Networking Fundamentals Review

Networking Fundamentals Review. Networking Evolution. Network: Two or more connected computers that share data Paradigms: Client/server model Mainframe model Peer to peer Web-based networking

marge
Download Presentation

Networking Fundamentals Review

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Networking Fundamentals Review

  2. Networking Evolution • Network: • Two or more connected computers that share data • Paradigms: • Client/server model • Mainframe model • Peer to peer • Web-based networking • Sneakernet:The transfer of files from one computer to another using a floppy disk or other removable medium

  3. Networking Categories • Two basic categories: • Server-based • Peer-to-peer • Enterprise networks • Combine peer-to-peer and server-based

  4. Network Topologies • Bus • Star • Ring • Hybrid networks • Mesh

  5. Layers of the OSI/RM • Application All • Presentation People • Session Seem • Transport To • Network Need • Data link Data • Physical Processing

  6. Application Layer • User interface • Supports file transfer • Network management • Accepts requests and passes them down to the presentation layer

  7. Presentation Layer • Converts text from what is viewable to the user to what is understandable to the computer • Passes data to session layer

  8. Session Layer • Establishes, manages, and terminates connections between cooperating applications • Adds traffic flow information

  9. Transport Layer • Reliable, transparent transport between end points • Supports end to end error recovery and flow control • Connection-oriented protocols reside at this layer

  10. Network Layer • Responsible for forwarding and routing datagrams • Connectionless protocols reside at this layer

  11. Data Link Layer • Provides reliable data transfer across the physical link • Frames are transmitted with the necessary synchronization error control and flow control • Prepares information so it can be sent to the physical wire

  12. Physical Layer • Concerned with the transmission of unstructured bit stream over a physical link • Responsible for the mechanical, electrical, and procedural characteristics to establish, maintain, and deactivate the flow of bits

  13. Application-Layer Protocols Network Management, File Transfers, User Interface • SNMP • SMB • X.500 • NCP • NFS • SMTP • BOOTP • FTP • HTTP • AFP

  14. Transport-Layer Protocols Reliable, Connection-Oriented, Error Recovery, and Flow Control • TCP • SPX • NWLink • ATP • NetBEUI

  15. Network-Layer Protocols Connectionless (best effort delivery), Forwards and Routes Datagrams • IP • IPX • NWLink • NetBEUI • X.25 • Ethernet

  16. Major Networking Protocols • Connection-oriented (stateful) • Connectionless (stateless) • Routable – Most protocols are routable • Nonroutable • NetBios • NetBeui • LAT • DLC

  17. TCP/IP • Default protocol for the following network operating systems: • Windows 2000 • Windows NT 4.0 • UNIX • NetWare 5 … plus the Internet! • Computers are each identified with an IP address and subnet mask

  18. IPX/SPX • IPX is responsible for forwarding packets to sockets • SPX ensures reliable data delivery and manages sessions • Must identify a frame type during setup

  19. NetBEUI • Non-routable • Fast • Easiest to configure and maintain • Low overhead

  20. AppleTalk • Used only on Apple Macintosh networks • Divides groups of computers into zones

  21. Common Network Components • NICs • Repeaters • Hubs • Bridges • Routers • Brouters • Switches • Gateways • CSU/DSU • Modems • Patch panels • Internet-in-a-box

  22. Network InterfaceCards (NICs) NIC is the interface between the computer and the network

  23. MAC Address Components

  24. Repeaters • Amplifies electronic signal • Strengthens signal by re-transmitting it when segment approaches its maximum length

  25. Hubs • Concentration point of network • Used with a star configuration

  26. Bridges • Operates on the data link layer • Reduce network traffic by dividing the network into two segments • Recognize mac addresses rather than IP addresses • Can connect two different topologies

  27. Routers • Operates on the network layer • Forwards or route data according to routing tables • Determine IP address needed and then most efficient route • Conserves network bandwidth by reducing broadcasting

  28. Switches • Can operate at the data link and network layers • Directs the flow of information from one node to another. • Faster because it give each sender/receiver the entire bandwidth of a line instead of sharing

  29. Gateways • Can operate at any level of the OSI model • Protocol converter – Appletalk to TCP/IP

  30. CSU/DSU • Channel Service Unit/Data Service Unit • Operates at the physical layer • Terminates physical connections • Used for bringing T1 lines into a building

  31. Modems • Uses POTS phone line to connect to internet • Can dial RAS connection directly to another computer

  32. Modem Initialization Commands AT – Precedes most commands ATDT – Dials the number ATA – Answers an incoming call manually ATH0 – Tells modem to hang up AT&F – Resets the modem to factory defaults ATZ – Resets modem to power up defaults , - Pause *70 or 1170 – Turns off call waiting

  33. Transmission Media • Twisted pair cable • Coaxial cable • Fiber optic cable • Wireless media

  34. Transmission Media • Twisted pair cable • UTP and STP • 100 meter length maximum • Twisted pair or 8 wires in 4 pairs, RJ-45 connectors • Category 3 – Ethernet 10BASE-T, 10mbps nics and hubs (16mbps maximum) • Category 4 – Used for token ring, generally at 16mbps (20mbps maximum) • Category 5 – Ethernet 100BASE-T, 100mbps nics and hubs (155mbps maximum)

  35. Transmission Media (cont.) • Coaxial cable • No concentrator is needed • Requires a terminator at each end • Thicknet - 500 meters, .5” (10BASE5) • Thinnet - 185 meters, .25” (10BASE2) • RG-58 cable, BNC connectors • Up to 255 devices can be attached to a single segment

  36. Transmission Media (cont.) • Fiber optic cable • Two strands of optical fiber, one sends, one receives, with pulses of light • FDDI and ATM technologies • 622 mbps (100-1,000mbps), 2,000 meters • Expensive and difficult to install • Very secure • No EMI • 100BASE-FX • Wireless media

  37. Port Numbers • Well-known port numbers • 25 – SMTP • 20, 21 – FTP • 110 – POP • 53 – DNS • 80 – HTTP • Numbers can also be assigned for security purposes

  38. Internet Addressing • Internet addresses are divided into the following parts: • Network • Host • Four fields separated by periods are a common notation for specifying addresses: • field1.field2.field3.field4 (222.41.1.25)

  39. 1 = On 0 = Off IP Address Fields • Contain eight bits per field • Range from 0 to 255 decimal field1.field2.field3.field4 1 1 1 1 1 1 1 1 = 8 128 64 32 16 8 4 2 1 = 255

  40. Internet Address Classes • Class A – 1-126 0 • Class B – 128-191 10 • Class C – 192-223 110 • Class D – 224-239 1110 • Class E – 240-247 11110

  41. IP Addressing Rules • Loopback addresses - 127.0.0.1 • Broadcast addresses - 255.255.255.255 • Network addresses - netid.255.255.255 • Special-case source addresses - 0.0.0.0

  42. Reserved (LAN) IP Addressing • 10.0.0.0 through 10.255.255.255 • 172.16.0.0 through 172.31.255.255 • 192.168.0.0 through 192.168.255.255

  43. Subnetworks • Subnet masks – used to distinguish network and host portions of addresses • efault subnet masks • Class A 255.0.0.0 • Class B 255.255.0.0 • Class C 255.255.255.0 • IPv6 – 128 bit address instead of 32 bit

  44. Diagnostic Tools forInternet Troubleshooting • ping • tracert • netstat • ipconfig • winipcfg • arp • network analyzers

  45. Internetworking Servers • File and print • HTTP • Proxy • Caching • Mail • Mailing list • Media • DNS • FTP • News • Certificate • Directory • Catalog • Transaction

  46. Fault Tolerance • Two primary types of drive fault tolerance: • RAID • Mirroring • Duplexing • Striping with Parity • Clustering • Backups

  47. Other Types ofData Protection • Uninterruptible Power Supply • Folder replication • Removable media

  48. Classifying Hackers • Casual attacker - 99.5% • Determined attacker - usually on ideological grounds, or a disgruntled employee

  49. Types of Attacks • Spoofing (masquerade) attacks - alters ip so it looks like it came from a trusted network • Man-in-the-middle (hijacking) attacks - capture packets sent between two hosts • Denial-of-service attacks - uses up all the system resources and crashes the system, usually with ping requests • Insider attacks – eavesdropping and snooping for information • Brute-force attacks - repeated logon attempts with a dictionary

  50. Types of Attacks • Trapdoor attacks - diagnostics programs can view and possibly execute system applications • Replay attacks - altered header info on packets to gain entrance to system • Trojan horse attacks – files placed on system by user that believes the program is a valid program, user executes • Social-engineering attacks – users tricked into giving out their personal information (this info is then used to crack passwords) • Front Door - stolen user name and password

More Related