Secrets! Principle of Internet Access Router

The performance and features of Internet access routers have been recognized by many people. The following describes the principles of Internet access routers, using proxy servers to access the Internet through dialing or ADSL is a cheap and practical method. For small and medium-sized enterprises, you can use routers to access the Internet. By using the proxy server software or Internet access router on the LAN, multiple users can access the Internet through sharing, which is essentially a bridge between the user group and the Internet, it is used to access the Internet by its network users.

How proxy servers access the Internet

Currently, all proxy servers are installed in a computer on the LAN in the form of software. The computer has an egress to access the Internet, the access method can be the 10/100 M Ethernet interface, ISDN, PSTN, or ADSL Of the man. The other Ethernet interface is generally interconnected with the internal lan. Due to the lack of valid IP addresses, an internal local area network generally uses illegal IP addresses. These IP addresses cannot be used as the source address of IP packets to access the external network. When a computer in the LAN needs to access the external network, the computer's access request is intercepted by the proxy server, the proxy server searches for the local cache, if the requested data (such as WWW page) if you can find the data, it is directly sent to the computer that sends the request in the Local Area Network; otherwise, the proxy server accesses the external network, obtains the corresponding data, and caches the data, at the same time, the data is sent to the requesting computer. However, the data in the proxy server cache must be constantly updated.

Use Internet Access Router

When using an Internet Access Router, you can use the (NAT) address translation technology to access the external network of an internal network if a valid IP address is missing. When a router receives an IP packet from a computer in the internal network that accesses the external network, it converts these illegal IP addresses into valid IP addresses and uses them as the source address of the IP packet to access the external network, when the returned data packet is configured by the router, the destination address of the data packet is converted to the Host IP address in the corresponding LAN, and the data packet is sent to the corresponding host, to access the Internet. These functions are actually part of NAT (network address translation. In addition to NAT, the router also uses firewall technology to access the Internet, mainly based on the source and target IP addresses and port filtering firewall technology. Through the firewall technology, the internal LAN can be protected from external attacks to a certain extent, playing a certain security role.

Select two access methods for comparison

In general, Internet access routers offer more benefits based on the following features. Vro provides powerful firewall and VPN functions. There are a variety of access methods. DDN and frame relay can be used. The overall network performance is better than that of the proxy server. The proxy server is installed on the computer, because the computer does not specifically process IP packets, so the performance is not very good.

You can easily publish WWW information. It is impossible to use the proxy server to establish a WWW website and provide WWW information to external sites. The reason is that the WWW server requires a valid IP address or maps the illegal IP address of the WWW server to a valid IP address through NAT. At the same time, sufficient capability is required to process external data requests. In this case, you can select an Internet access router. The overall investment is not very high. When a proxy server is used, for networks with many nodes in the LAN, because the computer dedicated to the proxy server cannot handle other work (otherwise, the network access to the external performance will be lower ), in contrast, investment in a vro and investment in proxy server software, coupled with a computer, is not very different.