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

Computer Operating System Our Game Plan Computer Networking Day 1: Introduction to Networking Day 2: IP address 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

Review of Day 1 Applications of Networks LAN, MAN & WAN Network Components (Physical Media, Interconnecting Devices, Computers, Networking Software and Applications)

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Introduction to Computer Networks IP address An IP address is a unique global address for a network interface An IP address: - is a 32 bit long identifier - encodes a network number (network prefix) and a host number

Introduction to Computer Networks IP address An IP address is a unique global address for a network interface An IP address: - is a 32 bit long identifier - encodes a network number (network prefix) and a host number

Dotted Decimal Notation Introduction to Computer Networks Dotted Decimal Notation IP addresses are written in a so-called dotted decimal notation Each byte is identified by a decimal number in the range [0..255]: Example: 10000000 10001111 10001001 10010000 1st Byte = 128 2nd Byte = 143 3rd Byte = 137 4th Byte = 144 128.143.137.144

Network prefix and Host number Introduction to Computer Networks Network prefix and Host number The network prefix identifies a network and the host number identifies a specific host (actually, interface on the network). How do we know how long the network prefix is? The network prefix is implicitly defined (see class-based addressing) The network prefix is indicated by a netmask. network prefix host number 128.143.137.144

IPv4 Address Classes Introduction to Computer Networks Class D Addresses A Class D address begins with binary 1110 in the first octet. First octet range 224 to 239. Class D address can be used to represent a group of hosts called a host group, or multicast group. Class E Addresses First octet of an IP address begins with 1111 First octet range 240 to 255. Class E addresses are reserved for experimental purposes and should not be used for addressing hosts or multicast groups. 

IP Addresses as Decimal Numbers Introduction to Computer Networks IP Addresses as Decimal Numbers

Introduction to Computer Networks Private Addresses

Introduction to Computer Networks DHCP a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (i.e., a scope) configured for a given network. DHCP allows a computer to join an IP-based network without having a pre-configured IP address. DHCP is a protocol that assigns unique IP addresses to devices, then releases and renews these addresses as devices leave and re-join the network.

Introduction to Computer Networks DHCP Internet service providers usually use DHCP to help customers join their networks with minimum setup effort required. Likewise, home network equipment like broadband routers offers DHCP support for added convenience in joining home computers to local area networks (LANs). DHCP environments require a DHCP server setup with the appropriate configuration parameters for the given network. Key DHCP parameters include the range or "pool" of available IP addresses, the correct subnet masks, plus network gateway and name server addresses.

DHCP Introduction to Computer Networks

Introduction to Computer Networks Gateway (router) A network gateway is an internetworking system capable of joining together two networks that use different base protocols. A network gateway can be implemented completely in software, completely in hardware, or as a combination of both.

Gateway (router) Introduction to Computer Networks

Network Address Translation (NAT) Introduction to Computer Networks Introduction to Computer Networks Network Address Translation (NAT) Network Address Translation (NAT) is designed for IP address conservation. It enables private IP networks that use unregistered IP addresses to connect to the Internet. NAT operates on a router, usually connecting two networks together, and translates the private addresses in the internal network into legal addresses. As part of this capability, NAT can be configured to advertise only one address for the entire network to the outside world. This provides additional security by effectively hiding the entire internal network behind that address.

Network Address Translation (NAT) Introduction to Computer Networks Introduction to Computer Networks Network Address Translation (NAT)

Wireless Communication (Wi-Fi) Introduction to Computer Networks Introduction to Computer Networks Wireless Communication (Wi-Fi) Wi-Fi allows networking of computers and digital devices without the need for wires. Data is transferred over radio frequencies, allowing Wi-Fi capable devices to receive and transmit data when they are in range of a Wi-Fi network. Wi-Fi, or Wireless Fidelity, is a term that is used generically to refer to any product or service using any type of 802.11 technology. Wi-Fi networks operate in the unlicensed 2.4 and 5 GHz radio bands

Wireless Communication (Wi-Fi) Introduction to Computer Networks Introduction to Computer Networks Wireless Communication (Wi-Fi)

Router Setup IP address DHCP NAT WIFI GATEWAY Introduction to Computer Networks Introduction to Computer Networks Router Setup IP address DHCP NAT WIFI GATEWAY

Thank you Day 3: Introduction to Operating System