Protocol Trip

For Real Experience in penetration testing VOIP with Backtrack. 
Use Following Link :-http://www.backtrack-linux.org/wiki/index.php/Pentesting_VOIP 

You can learn a lot while doing practical . In hacking World each and every protocol is important. Because of that you can enter directly to the Victims PC And perform lot of operation.

Network security protocols are used to protect computer data and communication in transit. The primary tool used to protect information as it travels across a network is cryptography. Cryptography uses algorithms to encrypt data so that it is not readable by unauthorized users. Generally, cryptography works with a set of procedures or protocols that manage the exchange of data between devices and networks. Together, these cryptographic protocols enhance secure data transfer.

Without cryptographic network security protocols, Internet functions such as e-commerce would not be possible. Secure communication is necessary because attackers try to eavesdrop on communications, modify messages in transit, and hijack exchanges between systems. Some of the tasks networks security protocols are commonly used to protect are file transfers, Web communication, and Virtual Private Networks (VPN).

The most common method of transferring files is using File Transfer Protocol (FTP). A problem with FTP is that the files are sent in cleartext, meaning that they are sent unencrypted and therefore able to be compromised. For example, many webmasters update their sites using FTP; an attacker using a packet sniffer and the website’s IP address can intercept all communications between the webmaster and the site’s server.

As an alternative, Secure File Transfer Protocol (SFTP) offers a more secure way to transfer files. SFTP is usually built upon Secure Shell (SSH) and is able to encrypt commands and data transfers over a network, thereby reducing the likelihood of interception attacks. The SSH cryptographic protocol is also resilient to impersonation attacks because the client and server are authenticated using digital certificates.

In addition to SSH, Secure Sockets Layer/Transport Layer Security (SSL/TLS) can be used as the underlying protocol for SFTP. Like SSH, SSL/TLS authenticates the identity of both the server and the client, as well as encrypts communications between the two. In addition to securing SFTP file transfers, SSL/TLS is used for securing e-mail communication.

SSL is also used in combination with Hypertext Transfer Protocol (HTTP) to encrypt communications between a browser and a web server in the form of HTTP over Secure Sockets Layer (HTTPS). HTTPS encrypts communications and verifies the identity of a web server. When performing private transactions over the Internet, such as online banking, it generally is good practice for a person to check the browser’s address bar to make sure that the website’s address begins with https:// and not just http://.

Another area where cryptographic network security protocols play an important role, especially for modern businesses, is in exchanging documents between private networks over a public Internet connection. These so-called Virtual Private Networks (VPNs) are critical for business because they securely connect remote workers and offices across the world. Some commonly used network security protocols that are used to facilitate VPNs are Point-to-Point Tunneling Protocol (PPTP), Layer 2 Tunneling Protocol (L2TP), IP Security (IPsec), and SSH. Not only do these network security protocols create a safe connection but they also greatly reduce the costs associated with creating an alternate solution, such as building or leasing lines to create a private network.