What is a VPN?

1. - Introduction:
A few years ago it was not as necessary to connect to the Internet for work purposes. As time has gone past companies have seen the need for local area networks overcome the barrier of local connectivity allowing staff and offices in other buildings, cities, regions and even countries.
Unfortunately, at the other end of the scale were the large investments were needed in both hardware and software and of course on telecommunications services that would create these service networks.
Fortunately with the advent of the Internet, companies, training centers, organizations of all types and even individual users are able to create a virtual private network (VPN) that would extract a moderate economic investment and using the Internet, the connection between different locations bridging the gap between them.
Virtual Private Networks using special security protocols that allow access to private services, only authorized personnel of enterprises, training centers, organizations, etc., When a user connects to the Internet, the network configuration VPN allows you to connect to the private network of the body with which to collaborate and access the same resources as if you were sitting quietly in his office.
2. - What is a VPN?
Brevity is a virtue, I said the great Quevedo: The good, if brief, twice good. Following that premise briefly try to explain that a VPN is a virtual network that is created within a real network, such as the Internet.
Really a VPN is not only a corporate network structure implemented on a network of public resources, but it uses the same management and the same access policies that are used in private networks, the end of the day no is more than creating a public network in an environment of confidentiality and privacy that allow the user to work as if on the same local network.
In most cases the public network is the Internet, but may also be an ATM or Frame Relay network
3. - How a VPN Functions:
As noted in a previous section, from the point of view of the user who is connected to it, running a VPN is similar to any normal network, but really so that the behavior is perceived as the same are a large number of elements and factors that make this possible.
The communication between the two ends of the private network through the public network is done by setting virtual tunnels between these two points and using encryption and authentication systems which ensure the confidentiality and integrity of data transmitted through the public network. Due to the use of these public networks, usually the Internet, it is necessary to pay special attention to the issues of security to prevent unauthorized access.
The tunneling technology (Tunneling) is a way of sending data which encapsulates a type of data packets within the data packet itself of any communications protocol, and upon reaching his destination, the original package is unpacked back and to their original state.
In the transfer over the Internet, packets is encrypted, for this reason, authentication techniques are essential for the correct operation of VPNs as to ensure that the transmitter and receiver are exchanging information with the user or correct device.
The virtual network authentication system is similar to login via username and password, but you have a greater assurance needs identity validation.Most authentication systems are used in VPN system based on shared keys.
Authentication is typically done at the start of a session, and then, randomly, during the course of the session, to ensure there is no any third participant that has been intrude on the conversation.
All VPNs use some form of encryption technology that packages data into a secure package to be sent over the public network.
The encryption must be considered as essential as authentication, allowing secure data transported be visible and understood on the trip from one end to another connection.
There are two types of encryption techniques used in VPNs: secret key encryption, or private and public key encryption.
In secret key encryption uses a secret password known to all participants that they will make use of the encrypted information. The password is used for both encryption and decryption information. This type of system has the problem that, to be shared by all participants and must be kept secret, to be revealed, has to be changed and distributed to participants, which can create security issues.
The public key encryption involves the use of two keys, one public and one secret. The first is sent to the other participants. When encrypting, using own private key and the public key of the other participant in the conversation. Upon receiving the information, it is decrypted using its own private key and public information generator. The great disadvantage of this type of encryption is that it is slower than the secret key.
In the virtual network, the encryption should be done in real time, thus encrypted information flows across a network using encryption are secret key keys that are valid for the currently used session.