Cyber security and ethical hacking 3
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The document discusses Network Address Translation (NAT) and its significance in managing IP addresses, improving security, and facilitating network management. It explains the difference between internal and external IP addresses, how NAT operates by assigning public IP addresses to internal devices, and the way it handles incoming and outgoing connections. Additionally, it covers various methods for bypassing internet restrictions, including proxy servers, VPNs, and HTTP tunneling, along with techniques for uncovering personal information online.
Cyber security and ethical hacking 3
- 1. Cyber Security & Ethical Hacking By Mehedi Hasan Lecture 3: NAT, Internal VS External IP Addresses, IP Address Hiding, Perfect Cyber Crime, Proxy Server, Unblocking Websites, People Hacking, VPN and HTTP Tunneling
- 2. IP Address When the internet was initially created, there was no shortage of IP addresses. However, as internet usage spread, an acute shortage of IP addresses was created was created worldwide. This led to the emergence of NAT of Network Address Translation. The biggest advantages of NAT are: • Reduces Need for IP addresses. • Improves security. • Easier implementation of Network. Internal IP Address and External IP Address Introduction to NAT
- 3. IP Address Let me give you an example to explain a NAT. Let us assume that there are 100 employee in an office. Every employee has a internal phone on their number with an extension number. There is a receptionist in the office who controls all incoming /outgoing phone calls in the office. We can call her NAT. The receptionist has a lookup table that contains a list of employee names and their respective extension numbers. Now look at how incoming and outgoing phone calls are handled. Outgoing call: Employee -----------Receptionist -----------------Target number. The person at the destination number will only see the mail office line phone number and not your internal desk number. This give you security & prevents annoying people from calling you. It also allows Internal IP Address and External IP Address Introduction to NAT
- 4. IP Address Incoming Call: Outside number ----------------Receptionist ----------Internal Extension When someone from outside the office wants to call you then they have to call on the office main number. The receptionist or automatic phone system will pickup the call and ask the outside to enter the extension number or name they want to speak to. Depending upon the extension number entered, the lookup table is used to route the call to the appropriate employee in the office. Internal IP Address and External IP Address Introduction to NAT
- 5. IP Address A NAT system operates in the same way. All employee in the office are giving unique internal IP addresses which normally can not be accessed from outside the network. When a internal computer wants to connect to the internet, then the router assigns the internal computer a public external IP address that has been bought by the company. The same public external IP address is shared by all computers in the network. The internal IP addresses of the employees remains protected, because outsiders are always only communicate with the public IP address of the company. Internal IP Address and External IP Address Introduction to NAT
- 6. IP Address For example, let us assume that there are 100 student in a collage and all of them have been assigned internal IP addresses: 10.95.1.23, 10.95.1.1……………..10.95.1.99. if student X (IP addresses is 10.94.1.23) wants to access a system Y onside the network, then the following will happen: • Step 1: Student X connects to router requesting an outside connection. Router knows student X’s internal IP address • Steps 2: Router allows the internal system to communicate with outside world using the networks public IP address. • Step 3: The router maintains a lookup table that maps different connections made by internal computers to various port numbers. Let un see an example to make this clearer. Internal IP Address and External IP Address Introduction to NAT
- 7. IP Address Step 3: The router maintains a lookup table that maps different connections made by internal computer to various port numbers. Let us see an example to make this clearer. Say there are two internal systems A (10.95.1.23) and B (10.95.1.1) and both of them initiate connections to the same website www.gmail.com. The public IP address of the network is 204.98.11.2, then the router will store the 2 connections in a lookup table in the following manner. 10.95.1.23 is stored as 204.98.11.2: port X 10.95.1.1 is stored as 204.98.11.2: port Y Gmail.com thinks it is communicating with only the public IP addresses 204.98.11.2. to send data to the internal system 10.94.1.0 gmail will send date to 204.98.11.2 and to send data to the internal system 10.04.1.1, gmail will send data to 204.98.11.2: Y Internal IP Address and External IP Address Introduction to NAT
- 8. IP Address Step 4: When the router of the college receives data from the remote computer, then the data is forwarded to the respective internal system based on the lookup table. Data send to the public IP address 204.98.11.2: X, is forwarded to the internal system 10.95.1.23 and data sent to the public IP address 204.98.11.2: Y , is forwarded to the internal system 10.95.1.23 . As simple as that. Internal IP Address and External IP Address Introduction to NAT
- 9. IP Address Internal IP address can be found out using the commands: Netstate –n Ipconfig /all External IP address can be found out by opening your browser and connecting to: www.whatismyipaddress.com Internal IP Address and External IP Address How to find out your internal IP address and external IP address?
- 14. Torrents How are Torrents Blocked? -Disable Torrent Clients. -Block Download of .torrent extension files
- 17. The Real Cyber Crime Proxy Bouncing (Hide your IP). Mac Spoofing (MacMakeup, Mad Macs, Ether Change, Bwmachak). WAR Driving (Connect to random wi-fi network). Onion Routing (Tor Encrypts Data + 3 Server Minimum)
- 18. IP Address How to unblock Tor?
- 19. IP Address • Change the name of the exe file. • Change the port being used by tor. • Add bridge relays to tor. How to unblock Tor?
- 21. IP Address bridges@bridges.torproject.org will get bridges in the body. Introduction to NAT
- 22. IP Scanning Types of Proxy Servers: Socks and http HTTP Proxy Server: Http Proxy server allow you to bypass filtering mechanism & access blocked control. User sends HTTP request to proxy server, who then reads the host header in the HTTP request, connects to the target server and transmits back whatever data the server sends back. Usually works with only HTTP apps. For example, www.anonymizer.com
- 23. IP Scanning Types of Proxy Servers: Socks and http HTTP Proxy Server: Http Proxy server allow you to bypass filtering mechanism & access blocked control. User sends HTTP request to proxy server, who then reads the host header in the HTTP request, connects to the target server and transmits back whatever data the server sends back. Usually works with only HTTP apps. For example, www.anonymizer.com Socks Proxy Server: Socks Proxy Server allow you to bypass filtering mechanisms & access blocked content. Socks is a protocol that transmits data between source and destination via a proxy server without reading any of the contents. Hence it works with all protocols like TCP, UDP etc and will allow you to use all applications (like mail, browsing, FTP, ets). For example tor.
- 24. IP Scanning MultiProxy : Allows you to keep changing proxy server the same session. Supports both HTTP & SOCKS proxy
- 25. IP Scanning SOCKSChain: Connects you to a chain of various SOCKS of HTTP proxies. (Proxy Bouncing)
- 26. IP Scanning You------------------Proxy Server------------Internet Proxy Bouncing You-------------Proxy Server------------Proxy Server 2---------- Proxy Server 3-------------Proxy Server 4-----------Internet
- 27. IP Scanning Proxifier: Allows you to connect multiple proxy server. The same session. Typically Socks Proxies.
- 28. IP Scanning Ultrasurf: Anonymous browsing from your pen drive, encrypts connection, hide your IP and unblocks stuff.
- 29. IP Scanning A VPN (Virtual Private Networks) is a group of computer connected together privately through a public network like the internet. Usually VPN services give you an encrypted secure and anonymous communication channel
- 30. IP Scanning Popular VPN Services: HideMyAss, IPVanish, Strong VPN, Box VPN, 12VPN, GoTrusted and others.
- 31. HTTP Tunneling Let us assume that in your college or company, FTP protocol (Port 21) is blocked or torrents are blocked. The firewall only allows HTTP traffic on port 80, all other ports are blocked. It is possible to encapsulate FTP or torrent traffic inside HTTP protocol and bypass the firewall. Step 1: Install HTTP Tunneling software server on your home or outside computer that has unrestricted access. Step 2: Install HTTP tunneling software client on your college or office computer that has restricted access.
- 32. HTTP Tunneling Step 3: Now your connection diagram will be the following: You ------------FTP or torrent software ------------HTTP Tunneling client -----------------sends FTP or Torrent traffic encapsulated into HTTP protocol via port 80 to bypass firewall --------HTTP Tunneling server on home computer -----------FTP or torrent destination. Now you can use college computer to access everything on your home network including unrestricted internet. Tunnelizer, HTTPort and HTTP Tunnel and so one.
- 33. Super Network Tunnel This is a commercial tool that perform two way HTTP tunneling . Not only can you access your home network from college. But you can access college network from home.
- 34. Super Network Tunnel PSIPHON: invitation only. Proxy server globally encrypted data communication.
- 35. Reverse Text .reverse in text the write to is china in used strategy http://textmechanic.com
- 36. Google Translate Unblock WebPages by converting them from one language to other translate google.com
- 37. Google Translate Unblock WebPages by converting them from one language to other translate google.com
- 38. Proxy Workbench Proxy workbench records all data passing through particular system in teal time. Fantastic to study how connections happen.
- 39. People Hacking Whatever you do online, you are leaving a trace behind on some website, server of system in some part of the world or other. People hacking is the technique of searching the entire internet looking for private information about some individual. The information that you can find out is the following. • Contact Addresses. •Date of Birth. •Email Address. •Contact Number. •Place of Work. •Satellite Photos. •Work History.
- 43. Proxy Workbench IptoMAC Coverts know IP to MAC Address.
- 44. Thanks You