ZyXEL Communications ZyAIR B-5000, Руководство пользователя

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ZyAIR B-5000 User’s Guide
Server Mapping 11-1
Chapter 11
Server Mapping
This chapter provides information on the Server Mapping screen.
11.1 TCP
Transmission Control Protocol is a connection-oriented transport service that ensures the reliability of
message delivery. It verifies that messages and data were received.
11.2 UDP
User Datagram Protocol (UDP) is a connectionless transport service that dispenses with the reliability
services provided by TCP. UDP gives applications a direct interface with the Internet Protocol (IP) and the
ability to address a particular application process running on a host via a port number without setting up a
connection session.
11.3 Server Mapping
The ZyAIR can forward traffic to a server with a private IP address (Virtual Server) behind the ZyAIR. In
this way it is visible to the outside world.
The
Protocol (TCP or UDP) and Port number define the service. For example, TCP port 80 is for web
(HTTP) service.
In addition to the servers for specified services, NAT supports a default server. A service request that does
not have a server explicitly designated for it is forwarded to the default server. If the default server is not
defined, the service request is simply discarded.
Many residential broadband ISP accounts do not allow you to run any server
processes (such as a Web or FTP server) from your location. Your ISP may
periodically check for servers and may suspend your account if it discovers any
active services at your location. If you are unsure, refer to your ISP.
The most often used port numbers are shown in the following table. Please refer to RFC 1700 for further
information about port numbers.
Table 11-1 Services and Port Numbers
SERVICES PORT NUMBER
ECHO 7