Évaluations - 0, GPA: 0
(
)
)
|
Par ce dispositif a également d'autres instructions :
Matériel de réseau - WNR1000v3 (3.24 mb)
Matériel de réseau - WNR1000v3 (3.03 mb)
Facilité d'utilisation
7. Upon receiving the incoming message to destination port 113, your router checks its session table and learns that there is an active session for port 113, associated with your computer. The router replaces the message’s destination IP address with your computer’s IP address and forwards the message to your computer. 8. When you finish your chat session, your router eventually senses a period of inactivity in the communications. The router then removes the session information from its session table, and incoming traffic is no longer accepted on port numbers 33333 or 113. To configure port triggering, you need to know which inbound ports the application needs. Also, you need to know the number of the outbound port that will trigger the opening of the inbound ports. You can usually determine this information by contacting the publisher of the application, or user groups or newsgroups. Note: Only one computer at a time can use the triggered application. How Port Forwarding Changes the Communication Process In both of the preceding examples, your computer initiates an application session with a server computer on the Internet. However, you might need to allow a client computer on the Internet to initiate a connection to a server computer on your network. Normally, your router ignores any inbound traffic that is not a response to your own outbound traffic. You can configure exceptions to this default rule by using the port forwarding feature. A typical application of port forwarding can be shown by reversing the client-server relationship from our previous Web server example. In this case, a remote computer’s browser needs to access a Web server running on a computer in your local network. Using port forwarding, you can tell the router, “When you receive incoming traffic on port 80 (the standard port number for a Web server process), forward it to the local computer at 192.168.1.123.” The following sequence shows the effects of the port forwarding rule you have defined: 1. The user of a remote computer opens Internet Explorer and requests a Web page from which resolves to the public IP address of your router. The remote computer composes a Web page request message with the following destination information: • The destination address is the IP address of which is the address of your router. • The destination port number is 80, the standard port number for a Web server process. The remote computer then sends this request message through the Internet to your router. 2. Your router receives the request message and looks in its rules table for any rules covering the disposition of incoming port 80 traffic. Your port forwarding rule specifies that incoming port 80 traffic should be forwarded to local IP address 192.168.1.123. Therefore, your router modifies the destination information in the request message: The destination address is replaced with 192.168.1.123. Your router then sends this request message to your local network. 3. Your Web server at 192.168.1.123 receives the request and composes a return message with the requested Web page data. Your Web server then sends this reply message to your router. 4. Your router performs Network Address Translation (NAT) on the source IP address, and sends this request message through the Internet to the remote computer, which displays the Web page from To configure port forwarding, you need to know which inbound ports the application needs. You usually can determine this information by contacting the publisher of the application or user groups or newsgroups. How Port Forwarding Differs from Port Triggering The following points summarize the differences between port forwarding and port triggering: • Port triggering can be used by any computer on your network, although only one computer can use it at a time. • Port forwarding is configured for a single computer on your network. • Port triggering does not need to know the computer’s IP address in advance. The IP address is captured automatically. • Port forwarding requires that you specify the computer’s IP address during configuration, and the IP address must never change. • Port triggering requires specific outbound traffic to open the inbound ports, and the triggered ports are closed after a period of no activity. • Port forwarding is always active and does not need to be triggered. Configuring Port Forwarding to Local Servers Using the port forwarding feature, you can allow certain types of incoming traffic to reach servers on your local network. For example, you might make a local Web server, FTP server, or game server visible and available to the Internet. Use the Port Forwarding screen to configure the router to forward specific incoming protocols to computers on your local network. In addition to servers for specific applications, you can also specify a default DMZ server to which all other incoming protocols are forwarded. The DMZ server is configured in the WAN Se...