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networks nd networking 2

Network Topologies
•There are three main local area network (LAN) topologies:
Bus
Star
Ring
•Other network topologies include:
Mesh
Wireless

What is a server?
•Server is a machine which provides services to the nodes or computers in a network and those computers using services are known as client machines.
•For each any every service client have to request to the server.

Client Server Model


  Servers
•Computers or processes that manage network resources
Disk drives (file servers)
Printers (print servers)
Network traffic (network servers)
•Example: Database Server
A computer system that processes database queries

Clients
•Application that run on a computer
•Rely on a server for
Files
Devices
Processing power
•Example: E-mail client
An application that enables you to send and receive e-mail

Types of Servers
•Application Servers
•Audio/Video Servers
•Chat Servers
•Fax Servers
•FTP Servers
•Groupware Servers
•IRC Servers
•List Servers
•Mail Servers
•News Servers
•Proxy Servers
•Telnet Servers
•Web Servers
•Etc.

Server or Services
•DNS is Domain name system/server/service but most of the people say that DNS is a Domain name server, it is a service and when anyone use the service from a machine then the machine or system is known as DNS server, because at that time that system is providing service to the client machine.
•Same as DHCP, FTP, Telnet, etc they all are services and whenever we use the services from the particular machine they’re known as the servers


 Types of address in a computer
•Logical address.
IP address
•Physical address.
MAC address

 What is an IP address?
•Numerical label assigned to devices participating in network that uses IP for communicating amongst themselves.
•Example: 192.168.1.3

 Types Of IP address
•IP V4
32 bit IP address.
•IP V6
128 bit IP address.

Main Classes of IP addresses:
•A class: 1 – 126 (describe here in very short)
•B class: 128 – 191
•C class: 192 – 223
•D Class:
•E Class:

Other range of IP addresses:
•D Class: 224 – 239
Used for multicasting.
•E Class: 240-255
Used for Research and Development (R&D).

Special IP Addresses

 •127.0.0.0 Universal loop back address.
•169.254.0.0 APIPA (Automated private IP Addressing)
•Private IP Address Range
▫192.168.*.*
▫172.16*.*.*
▫10.*.*.*
•0.*.*.*

 Subnet mask
•It shows the number of Network and hosts.
 Say for
C class: IP Address: 192.168.10.23
Default Subnet mask: 255.255.255.0
•Why we use it? (Answer it)

 Default gateway
•Default gateway is the IP address of the machine or system, through which you’re able to use the Internet network.
•To access the default gateway, type the IP address of the system in URL bar.
•Example: http://192.168.1.23

 To know your IP address
•Step 1: Open cmd
•Step 2: C:/ipconfig
or
ipconfig \all

  IP v4 IPv6
•32 – bit address
•Dotted decimal notation: 192.168.1.2
•Number of addresses:
4.2 billion
•128 – bit address
•Hexadecimal notation 3FEE:FAAA:0093:BDBD:AAC3:345C:03AB:003E
•Number of addresses:
3.4×1038

 Port
•A logical number allow software applications to share hardware resources without interfering each other.
•Example:
Port# 22 – SSH
Port# 80 – HTTP
Port# 443 – HTTPS
Port# 21 – FTP

 Programming Language
•Artificial language designed to express computations that can be performed by a machine, particularly a computer
•Programming loopholes
•The flaws in the programming which can be exploited.
•Most of the attacks are nothing but loopholes of some kind

 Types of programming languages:
•C
•C++
•Java
•ASP
•PHP
•Perl
•Python
•Shell scripting

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