Ppt On Network Security

PRESENTS

Presentation on Network security PRESENTED BY: ABHISHEK RAJVAIDYA FIRDOS KHAN

WHAT IS NETWORK SECURITY? 

Network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network and the networkaccessible resources from unauthorized access and consistent and continuous monitoring and measurement of its effectiveness (or lack) combined together.

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INTERNET PROTOCOL ADDRESS:-It represents your identity on the internet. it is the address to which all data is sent. It contains information about the network to which you belong and the part of world in which you live.

Netstat make easy 

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The netstat command can be used to gather information on a variety of different aspects of your system’s communication state at a given point of time including a list of open connections ,protocols, list of open ports remote ip address details etc. ENUMERATION THROUGH INSTANT MESSAGING SOFTWARE:THROUGH ICQ(I SEEK YOU) XX.XX.XX.XX -> YY.YY.YY.YY (YOU) (YOUR FRIEND) LAUNCH MS-DOS TYPE NETSTST-N LAUNCH ICQ AND SEND A MESSAGE TO THE VICTIM WHILE YOU ARE CHATTING RETURN TO MS-DOS AND AGAIN ISSUE THE netstat-n COMMAND.YOU WILL FIND A NEW IP SIGNIFYING A NEW CONNECTION.THIS IS THE VICTIMS IP ADDRESS.

OTHER INSTANT MESSENGERS Whenever you start a chat session with a friend on IM an indirect connection b/w you and your frd is established 

xx.xx.xx.xx -> msn server-> yy.yy.yy.yy (you) (your friend) Similarly all the messages that your frd types reach you in the following manner yy.yy.yy.yy -> msn server ->xx.xx.xx.xx Open ms-dos prompt enable file sharing and type netstat –n command and a direct connection is established

prevention  First

and most simple do not accept any file transfers or call requests from people you do not trust.  Install a firewall on your system that does not respond to external packets coming from untrusted sources.  Chat through proxy servers like wingate,winproxy,and many others

Hiding your ip address  NAT

NETWORKS

Typically in NAT network consists of a large number of internal systems that are connected to the internet through a routing device known as a NAT box. this NAT box acts as the core and controls all routing ,addressing and interfacing requirements of the network. IF an external system communicates with two internal systems in a NAT network at the same time ,it will be impossible it to differentiate b/w two systems Internal system(10.0.1.2 port number:1024)------NAT BOX------public ip address(171.134.110.24 port number 52341)

Drawback of NAT network  External

system cannot initiate connections with systems behind the NAT box. this is because the external routers will not know how to route packets addressed to the internal IP addresses of systems behind the NAT box.

PROXY SERVERS A proxy server protects the identity of your system from wilderness of the internet by acting as a buffer b/w you and the remote host to which you are connected. your system-> proxy server->remote host Remote host->proxy server->your system