Network Communication Between Local Devices and Remote Devices

This article aims at clarifying the difference between a “Local IP Address” assigned by a “Local Network” and a “Remote IP Address” assigned by a “Remote Network”.

Your ISP ( Internet Service Provider ) provides you with an “Internet Connection”. The communication between your business or home with your ISP is handled by a device called a “Modem”. Your modem is what produces an “IP Address”. The IP Address from the modem is a “Remote IP Address” or an “External IP Address”. This would be your unique identity on your ISP’s network. You could argue this would also mean your unique identity on the World Wide Web.

If you have more than one device at your business or home, you would typically have a device called a “Router”. The router provides what’s referred to as a “Network”. This network is an “Internal Network” or a “Local Network”. The router assigns each device on your internal network with a “Local IP Address” or “Internal IP Address”. This is different than the IP Address assigned by your ISP through your modem.

Each device that’s connected through your router has it’s own unique local IP Address. Part of the router’s job is to translate the local information to the modem, so that the modem can then communicate with your ISP.

Essentially, any information that is downloaded or uploaded from ANY device on your local network within your business or home is treated as one singular IP Address. This would be the “Remote IP Address” or “External IP Address”, provided by your modem.

The flow of information is as follows…

  1. If you were to “download” information from the internet:
    WWW ( World Wide Web -- A/K/A "the Internet" ) -> ISP -> Modem -> Router -> Local Device
  2. If you were to “upload” information to the internet:
    Local Device -> Router -> Modem -> ISP -> WWW ( World Wide Web -- A/K/A "the Internet" )

To summarize everything… Anything you do on the internet within your business or home is handled by one singular unique IP Address.

If you provide a WIFI connection to your customers/guests the end result is the information is still treated as one singular IP Address. Even if you split your “local network” into separate isolated local networks; One for employees/residents and one for your customers/guests. The internet still looks at it as one IP Address.

I would still recommend having separate local networks for your employees/residents and for your customers/guests. So that your customer/guest devices cannot communicate with your business/home devices.

If you wanted to truly separate the networks at an “Internet Level” (so to speak), you would need to request multiple static “External IP Addresses” from your ISP. You would then need to configure your router to assign each static External IP Address to each isolated local network. That way what ever your business/home does on the internet or what your customers/guests do on the internet are perceived as separate IP Addresses on the World Wide Web.

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