The concept of Extranet first appeared in the autumn of 1996. It connects enterprises and their suppliers or other trading partners. It is behind the firewall like Intract. But it does not only serve the internal enterprise like Intranet. Unlike the Internet, which is completely open to the public, it is only selectively open to the outside world. The information of the external network is secure under the protection of strict and effective security mechanisms, which can prevent information from leaking to unauthorized users. The authorized user can openly connect to the network of other enterprises through the external network. The extranet provides special facilities for enterprises to coordinate procurement. Exchange business documents through EDT to achieve mutual exchange and communication. The external network can use the Internet protocol and technology to communicate. The external network can be any of the following network types: public network, secure (private) network or virtual private network (VPN), which can realize information sharing between enterprises.
1、 Public network
If an organization allows the public to access the internal network of the organization through any public network (such as the Internet), or two or more enterprises use the public network to connect their internal networks, the external network of the public network will appear. In this structure, security is a big problem, because the public network does not provide any security protection measures. In order to ensure the security of transactions between cooperative enterprises, each enterprise must provide security protection for its information before sending it to the public network. Internal networks generally use firewalls to check packets from the Internet, but firewalls are not 100% secure. This is why the public network extranet is seldom used in practice, because the risk is too great. Both private networks and virtual private networks can provide sufficient security protection to meet the needs of transactions between enterprises.
2、 Private network
A private network is a special line connection between two enterprises. This connection is a physical connection between the internal networks of two enterprises. Dedicated refers to a permanent dedicated line connection between two points. Unlike ordinary dial-up connections, dedicated lines are always connected. The biggest advantage of this connection is security. Except for these two enterprises that are legally connected to the private network, no other person or enterprise can enter the network. Therefore, the private network ensures the security and integrity of the information flow. The biggest disadvantage of private networks is that the cost is too high, because private lines are very expensive. Every pair of enterprises that want to use private networks need an independent private line to connect them together. For example, if an enterprise wants to establish a connection with seven enterprises through a private network, it must pay for seven special lines. So should enterprises establish a close and dedicated connection between their intranets like JfJ? The answer may be an extranet based on virtual private network design.
3、 Virtual Private Network (VPN)
Virtual Private Network (VPN) extranet is a special kind of network. It uses a system called "channel" or "data encapsulation" to send sensitive data to trading partners, customers, suppliers and employees using public networks and their protocols. This channel is a private channel on the Internet, which can ensure the safe transmission of data between enterprises on the extranet. Since the most sensitive data is under the strictest control, VPN also provides security protection. VPN is like a separate sealed bus channel on the highway (Internet). Vehicles outside the bus channel cannot see passengers in the channel. By using the VPN dedicated channel established on the Internet, the enterprise employees in different places can send sensitive information to the enterprise computers. This kind of protected channel scheme between external network partners has developed rapidly, and the cost is also very low. Most external networks are LAN LAN type external networks or client/server type external networks. The early system (such as EDI) is the representative of LAN LAN type. Now the client/server type extranet is popular.
If an enterprise wants to establish closer ties with its suppliers or trading partners, it can use VPN to connect with them. The establishment of VPN does not require a dedicated line. In addition to the internal network of each company, the only required facility is the Internet. The installation and maintenance of VPN is becoming easier and easier. People often talk about the external network and VPN. Although VPN is an external network, not every external network is a VPN. Website Design Virtual private network can save costs. Although its main purpose is to create a competitive advantage by using the alliance between cooperative enterprises, unlike private networks that use private lines, the word "virtual" in VPN means that this connection looks like a permanent intranet connection, but it is actually temporary. Once a transaction occurs between two intranets, VPN will be established and the transaction will be conducted through the Internet; After the transaction is completed, the connection is terminated.
