ControlByWeb WEBRelay-10+ User Manual page 24

WebRelay-10 Plus™ Users Manual
Figure Appendix C.1 - Local Area Network
A Simple LAN connected to the Internet
The LAN in the example above can be connected to the Internet by adding a router and an Internet connection.
The router has two network connections. It has an Ethernet network connection that connects to the LAN, and it
has another connection that connects to the Internet (this is called the WAN or Wide Area Network connection).
Each network connection on the router has an IP address. In our example, the IP address on the LAN side of the
router has an address of 192.168.1.1. The IP address on the WAN side of the router has an IP address that has
been assigned by the Internet Service Provider such as 266.70.164.97 (note that this is not a valid IP address
because each number cannot be larger than 255, but it is used in this example for illustration purposes only).
Figure Appendix C.2 - LAN Connected to the Internet
In the example, when a user on the computer needs to access a server on the Internet, the computer sends the
request to the router at 192.168.1.1. The router sends the request to the server on the Internet. The server does
not send the response directly to the computer on the LAN, but to the router at the IP address of 266.70.164.97.
The router then forwards the response to the computer. This way, all devices on the LAN share a single public IP
address. This is called Network Address Translation.
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