Welcome to Early Bird Class Networking And IT Security Ravi Chandra Gurung

Game Plan

Our Game Plan Computer Networking Day 1: Introduction to Networking Day 2: IP addresses system DHCP Gateway NAT Router Setup Computer Operating System Day 3: Introduction to Operating System Day 4: Basic Linux Command OS Installation File Sharing Day 5: Web Server Configuration DNS Server Configuration FTP Server Configuration Computer Security Day 6: Introduction to Security Types of attack Process of attack Introduction to Hacking tools and techniques Counter Measures against attack

What is a “Network”? Introduction to Computer Networks A network is a way to get “stuff” between 2 or more “things” Examples: Mail, phone system, conversations, railroad system, highways and roads.

Applications of Networks Introduction to Computer Networks Resource Sharing Hardware (computing resources, disks, printers) Software (application software) Information Sharing Easy accessibility from anywhere (files, databases) Search Capability (WWW) Communication Instant messaging Voice/Video Conference Remote computing Distributed processing (Cloud Computing)

LAN, MAN & WAN Introduction to Computer Networks Network in small geographical Area (Room, Building or a Campus) is called LAN (Local Area Network) Network in a City is call MAN (Metropolitan Area Network) Network spread geographically (Country or across Globe) is called WAN (Wide Area Network)

Network Components Introduction to Computer Networks Physical Media Interconnecting Devices Computers Networking Software Applications

Networking Media Networking media can be defined simply as the means by which signals (data) are sent from one computer to another (either by cable or wireless means). Introduction to Computer Networks

Coaxial cable A central conductor wire Surrounded by an insulating material Surrounded by a braided metal shield Introduction to Computer Networks

Twisted pair Most common network cabling Twisted pairs of cables, bundled together Introduction to Computer Networks Shielded twisted pair (STP) Unshielded twisted pair (UTP)

Registered Jack (RJ) connectors RJ-11 (two pairs of wires) for telephones RJ-45 (four pairs of wires) for networks Introduction to Computer Networks RJ-11 (top) and RJ-45 (bottom) connectors

Fiber-optic Fiber-optic cable transmits light Not affected by EMI (Electromagnetic interference) Excellent for long-distance transmissions Single copper cable works up to a few hundred meters Single fiber-optic cable works up to tens of kilometers Introduction to Computer Networks

Composition of fiber-optic Core: the glass fiber Cladding: reflects signal down the fiber Buffer: gives strength Insulating jacket: protects inner components Introduction to Computer Networks Cross section of fiber-optic cabling

Fiber-optic light sources Two possible light sources Light Emitting Diodes (LEDs) – called multimode Lasers – called single-mode High transfer rates over long distances Introduction to Computer Networks

Networking Devices Introduction to Computer Networks HUB, Switches, Routers, Wireless Access Points, Modems etc.

Hub & Switch Introduction to Computer Networks Connects multiple computers or other network devices together. Send information and broadcasts all network data across each connection. Hub Switch Device that channels incoming data from any of multiple input ports to the specific output port that will take the data toward its intended destination.

Router & Access Point Introduction to Computer Networks A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. Routers are located at gateways, the places where two or more networks connect. Router Access Point Wireless access points (APs or WAPs) are special-purpose communication devices on wireless local area networks (WLANs). Access points act as a central transmitter and receiver of wireless radio signals

Firewall Introduction to Computer Networks A firewall is a network security system, either hardware- or software- based, that controls incoming and outgoing network traffic based on a set of rules.

Computers: Clients and Servers In a client/server network arrangement, network services are located in a dedicated computer whose only function is to respond to the requests of clients. The server contains the file, print, application, security, and other services in a central computer that is continuously available to respond to client requests. Introduction to Computer Networks

Type of Servers Application Server: Also known as a type of middleware, it occupies a substantial amount of computing region between database servers and the end user, and is commonly used to connect the two. Audio/Video Server: It provides multimedia capabilities to websites by helping the user to broadcast streaming multimedia content. FTP Server: It works on one of the oldest of the Internet services, the file transfer protocol. It provides a secure file transfer between computers while ensuring file security and transfer control. Mail Server: It transfers and stores mails over corporate networks through LANs, WANs and across the Internet. Introduction to Computer Networks

Type of Servers Introduction to Computer Networks Virtual Servers: A virtual server is just like a physical computer because it is committed to an individual customer's demands, can be individually booted and maintains privacy of a separate computer. Basically, the distance among shared and dedicated (hosting) servers is reduced providing freedom to other customers, at a less cost. Now, it has become omnipresent in the data center. Web Server: It provides static content to a web browser by loading a file from a disk and transferring it across the network to the user's web browser. This exchange is intermediated by the browser and the server, communicating using HTTP. Name Server: It is a computer that is permanently connected to the Internet and translates domain names into IP addresses (or vice versa), enabling you to enter instead of

Peer-to-Peer Introduction to Computer Networks a type of network in which each workstation has equivalent capabilities and responsibilities. a single software program designed so that each instance of the program may act as both client and server, with the same responsibilities and status.

Protocol Concepts Protocols are sets of rules. What do you want to do? (Application) Where are you going? (Addressing) How do you get there? (Media types) Did you get there? (Acknowledgments, Error checking) Introduction to Computer Networks

Networking Protocol: TCP/IP Suite Introduction to Computer Networks What do you want to do? Did you get there? (Acknowledgments, Error checking) Where are you going? Addressing How do you get there? (Media types)

Applications Searchable Data (Web Sites) E-Commerce News Groups Internet Telephony (VoIP) Video Conferencing Chat Groups Instant Messengers Internet Radio Introduction to Computer Networks

Thank you Next Class Day 2: IP address system DHCP Gateway NAT Router Setup