The rapid development of the Internet has made it easier for people to publish and retrieve information, but it also makes it easier to tamper with and destroy information. In order to protect the security of data and resources, routers have been created. A router firewall is essentially a protection device that protects the reputation of network data, resources, and users.
Data refers to the information that users store on their computers. There are three typical characteristics of data that need to be protected:
(1) Confidentiality: refers to users who do not want others to know their own information. (2) Integrity: It means that users do not want others to modify their own information (3> Usability: refers to users who want to use information resources to refer to users. Data, files, etc. in the computer.
There is no reputation problem in the computer itself. The problem is that a person invaders will pretend to be your identity and appear on the Internet, doing something that is harmful to others; or pretending to be your identity to consume online. Domestic and foreign sources show that there are generally several types of invaders: mischief, destruction, and espionage.
The router firewall is originally intended to refer to a partition wall in a building that is used to prevent the spread of fire. In theory, the principle of the Internet router firewall service is similar, it is used to prevent various types of danger on the Internet from spreading to your network. In fact, the router firewall service is used for multiple purposes:
Restrict people from entering a particular node;
Prevent people from invading your defense facilities;
Qualifying people to leave from a special node;
Participate effectively to prevent vandals from damaging your computer system.
Internet router firewalls are often installed on the connection nodes of the internal network and the Internet, as shown in Figure 7-1-1. As you can see from the figure, all information from the Internet or information sent from the internal network must pass through the router firewall, so the router firewall can ensure the security of information exchange such as e-mail, file transfer, remote login and specific systems.
Logically, the router firewall is a splitter, limiter, and analyzer; from a physical point of view, the physical implementation of each router firewall is different, it is often a set of hardware devices (such as routers, hosts, etc.) and software. A combination of products.