Revision 1.1
WebSwitch™ Users Manual
Using the mailing address analogy, the port is similar to a post office box. The IP address specifies the
location, and the port specifies the specific recipient. Port numbers can be set to any number between 1
and 65235; however, many port numbers are reserved for specific applications and should be avoided.
As a general rule, numbers above 8000 are safe to use. All of the ControlByWeb™ products come from
the factory with the HTTP port set to 80 which is the standard port for HTTP. In this example,
WebSwitch™ HTTP port will be changed to port 8000 and the WebRelay™ port will be changed to 8001.
Once the ports are changed in the two ControlByWeb™ devices, the router must be set up for port
forwarding. The way this is setup is specific to the router, but many routers use a table. Port forwarding
setup associates the IP address of each device with the assigned port. In this example, the address
192.168.1.25 (WebSwitch™) would be associated with port 8000. The address 192.168.1.26
(WebRelay™) would be associated with port 8001. By doing this, WebSwitch™ can be accessed from
the Internet by entering the public IP address of the router, plus the port number assigned to
WebSwitch™ in the URL window of the browser. For example, the user would enter
http://266.70.164.97:8000. When the router receives this request, it would look in its port forwarding
table to find out what to do with a request for port 8000. It would find that it should forward the request to
the local address of 192.168.1.25 and would then forward the request. The WebRelay™ could be
accessed the same way, except it would use port 8001 (http://266.70.164.97:8001).
Note: When an HTTP request comes in to the router without the specific port specified
(http://266.70.164.97), the router will handle this as a port 80 request (default HTTP port). In other
words, http://266.70.164.97 is exactly the same as http://266.70.164.97:80.
An example screen shot of a router configuration is given below. This setup allows the two
ControlByWeb™ products in the above example to be accessed remotely from the Internet.
Note: This screen shot is simply an example of a typical router setup page. Routers will vary.
Xytronix Research & Design, Inc.
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Figure Appendix C.3- Port Range Forwarding