LAN IP Address vs WAN IP Address
Question
What is the difference between LAN IP address and WAN IP address
of a network device?
Answer
A network device, i.e. network/LAN adapter, modem, router, access
point, can have a single IP address (either LAN or WAN IP address)
or two IP addresses (both LAN and WAN IP addresses). To clarify this
point, I would like to depict three Internet access scenarios as
follows:
1) A computer connects to Internet via an internal/external modem
that has no router functionality.
- This computer IP address is similar with the modem IP address, i.e. a WAN IP
address (public IP address) which is assigned by the ISP, such as
194.223.19.212.
2) A computer connects to Internet via an external modem that has
router functionality.
- This computer (i.e. the network adapter that
connects it to the modem) will have a LAN IP address (private IP
address) such as 192.168.1.2.
- Meanwhile the modem will have a LAN IP
address (private gateway IP address) such as 192.168.1.1 toward the connected computers and
a WAN IP address (public IP address) toward the ISP.
3) A computer connects to Internet via a wired/wireless router which
in turn connects to Internet via a broadband (DSL/cable/3G/3.5G/4G)
modem.
- This computer (i.e. the network adapter (Ethernet/Wi-Fi/Bluetooth)
that connects it to the modem) will get a LAN IP address (private IP
address) such as 192.168.2.3.
- The router will have a LAN IP address (private gateway IP address) such as
192.168.2.1 and a WAN IP address (also a private IP address) such as
192.168.1.2.
- The broadband modem which borders the LAN
(home/company/organization network) with the WAN (Internet) will have a
LAN IP address (private gateway IP address) such as 192.168.1.1 and a WAN IP
address (public IP address) toward the ISP.
The breakdown on configuration number 2 or 3 above also applies if this
computer is an ICS (Internet Connection Sharing) client that connects to
Internet via an ICS host because the ICS host acts as a router.
You can check your computer IP address and find out which network
card or adapter that connects you to the Internet by typing
ipconfig /all on the Command Prompt. To check your
modem or router LAN and WAN IP addresses, you can type its pre-defined
address on a browser (IE, Mozilla Firefox, Chrome, etc.) address bar,
e.g. http://192.168.1.1 and see the connection details
usually on a Home/Status page.
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