Sharing a mobile broadband connection

Here is how to share a mobile broadband connection with more than one client.

These notes describe using a Verizon wireless USB modem, a Windows host PC, Internet Connection Sharing (ICS) and a typical router with WiFi to share the mobile broadband connection to multiple clients, both wired and WiFi.

ICS diagram

Although there are instructions available for sharing an Internet connection (ie at Microsoft link1 link2 and annoyances.org link), these notes include using a typical router for the WiFi feature.

When using a typical broadband router in this scenerio, you must remember 3 things:  1) connect your host PC and client PCs to the LAN ports.  Do not use the Internet port! 2) turn off DHCP on the router and 3) configure the router LAN IP to be 192.168.0.2.

ICS does a good job sharing out the Internet connection but it insists on you playing by its rules:  ICS assigns 192.168.0.1 to the host PC LAN connection and does all DHCP functions.  This is why you have to configure the router to a LAN address other than 192.168.0.1 (192.168.0.2 works) and turn off all DHCP functions on the router.

These instructions assume some knowledge of configuring network connections and router configuration:

1.  Configure the router.  Connect a LAN cable from the host PC to a LAN port on the router.  Log on to the router.  Turn off DHCP. (The reason for this is ICS will function as the DHCP server.)  Assign the router a static LAN IP 192.196.0.x, for example 192.168.0.2.  (The reason for this is ICS will assign 192.168.0.1 to the host PC LAN connection and we don’t want any IP address collisions.)

2.  Configure the host PC.  Connect your wireless broadband USB modem card and configure it, make sure it works stand alone.  Open Network connections and identify your broadband modem (it may show up as a Dial up connection) and your Local Area Connection.  Configure the broadband modem for ICS:  right click on its icon, Properties, Sharing, check “Allow other network user to connect through this computer’s Internet connection” and for the Home networking connection select your Local Area Connection in the drop down list.  Note ICS will assign 192.168.0.1 to your Local Area Connection NIC and act as DHCP server, assigning client IPs, subnet mask, gateway IP and DNS server.

3.  Configure clients to “Obtain IP addresses automatically.”  (You can manually assign IP/subnet/gateway/DNS info but automatically is easier.)

Reboot everything to reset IP addresses and make sure everything works.  Note that the host PC needs to be booted up first so it can act as DHCP server to the clients.

Review security settings on your firewalls and router.

Enjoy sharing the Internet!

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