How to Add a Mobile Wireless Hot Spot to Your Network

One Methods:  At Home (Apple Time Capsule, T-Mobile 4G Hotspot, WET610N)

So you have a cellular phone or dedicated 'hot spot' gadget. It's OK for connecting one or two computers to the internet, but it is insufficient for a wireless network on its own, sending backups to network attached storage, moving files between computers, etc. You probably have a router/switch to do all of that grunt-work, but connecting to the wireless device is a problem.

Three words:  WIRELESS ETHERNET BRIDGE

Steps

1. Shop for a wireless ethernet bridge.
 A web search for 'wireless ethernet bridge' will turn up lots. Be sure to download and read the manual for the device, so you know what you'll be getting yourself into.

2. Configure the ethernet bridge to connect to your 'Wi-Fi Hotspot' gadget/phone/etc..
Be sure you use the RIGHT password, as it generally won't tell you that you've messed up. Every device is different. Most come with some software. Most have a 'web page' interface to configure it without the software. Read the manual.

3. Plug the bridge into your router or switch. 
If it's a switch, you're done. If it's a router, make sure it's plugged into the 'WAN' port.

4. Configure the router to 'bridge' mode. 
The DHCP on the wireless device will handle everything.

5. If it's a wireless router, only make sure it's a different name from the wireless network that the 'Hot Spot' provides.

6. Plug your computers, printers, etc. into the router/switch.

7. Everybody should have an internet connection, and all of the 'high speed' connection activity will bypass your 'Hot Spot'

> At Home (Apple Time Capsule, T-Mobile 4G Hotspot, WET610N)

1. Configure the 'Wireless Hot Spot'. 

The default password isn't easy to remember, and all numeric, which makes it supremely weak against attack. Mine had the 'Manual' inside it, along with the web interface. Once the software for it was installed, setup was easy, if you are used to setting up Wi-Fi devices.

2. Configure the 'Wireless Ethernet Bridge'. 
This was a LOT more difficult. The 'Wi-Fi Protected Setup' did not work. It didn't come with OS X software, and the 'Mac software' on their support site doesn't install. So I had to track down how to configure the web interface (Web Search: Installing WET610N using the Web-Based Setup Page). Connect it to the 'Hot Spot', and get the password RIGHT.

3. Plug the Wireless Ethernet Bridge into the WAN port of the router.

4. Configure the Router to connect to the Wireless Ethernet Bridge, using 'Airport Utility'. 
In this case, a 'Time Capsule 2TB'. 'Connect Using': Ethernet. 'Connection Sharing':Off (Bridge Mode).]

5. Optional:

 Instead of 'Bridge Mode', Disable DHCP on the wireless hot spot, then use 'Connection Sharing: Distribute a range of IP addresses', and manually configure the IP addresses for 'hot spot', router and DHCP addresses so they don't conflict. Configuring this way 'may' require you to change the settings back on the 'hot spot' when you hit the road and want to share the connection again. On the plus side, this will definitely work around any 'limits' the 'hot spot' has on number of active connections.

6. Connect all of your computers to the router's wired or wireless connections.

They should all share the internet connection whenever the wireless hot spot is turned on and in range of it.

Tips

• You may want to statically set the 'hot spot', ethernet bridge and router IP addresses. It simplifies administration greatly. For instance, with the WET610N, if your network is '192.168.1.*', but the WET610N configuration is '169.254.1.250' by default, it can become unreachable for configuration once everything is up and running. So if you leave the 'Hot Spot' at 192.168.1.1, 192.168.1.2 as your router, and set up 192.168.1.3 as your bridge (and keep these numbers out of the range of your DHCP), then you can go to 'http://192.168.1.3' to reach the bridge configuration, rather than have to unplug everything, plug your bridge into the computer, re-configure the ethernet port to a compatible address, configure, than plug it all back in right again.
• The 'Time Capsule' has more options under the 'Wireless Mode', if you hold down Option (alt) when you click it in the Airport Utility. However, connecting to the 'Hot Spot' as a client will disable your Time Capsule Wi-Fi, AND (quite evilly) disable the built-in ethernet ports. You can still connect to the Wireless Internet device its self, but these mobile things are pretty weak/slow to do backups through as the 'heart' of your network.
• Google provides a nice public DNS at 8.8.8.8/8.8.4.4. The DNS for some ISPs is awfully slow. However, using a DNS outside of the built-in 'Hot Spot' router's DNS may 'hide' its administrative tools from your web browser. So keep that in mind.
• Any storage that your cellular device shares over its USB connection will show up on the Time Capsule network shares if you plug it into its USB port for power, as another shared hard drive. If you're using a cell phone with a camera as your 'Hot Spot', and your name is 'Weiner', you might want to make sure that data isn't shared to everyone else on your network.
• If you have a few old wireless routers lying around, re-read their manuals before buying a bridge. Even if you lost the manual, the manuals for these can be found online. One may have a 'bridge' mode built in that can connect to an existing wireless network and add devices on its ethernet ports to the network.
• The 'T-Mobile 4g Hot Spot' needs to be manually disconnected from the internet through its web interface before most of its internal settings can be changed.
• READ THE MANUAL. It's not optional. Every network device is prone to some idiosyncrasies.
• Remember, every device has a way to reset it back to factory default. You can't 'lock yourself out' as long as you have a pin or pen to poke in the little recessed hole. Note: Most require you to HOLD that button in for several seconds, until lights start flashing.

Warnings

• Don't 'extend' a network that doesn't belong to you.
• Use nice, LONG, SECURE passwords containing mixed case letters, numbers and symbols. Write them down and file them away. Unless you want 'pedobear' browsing porn, or hacking government web sites from his van across the street... directly through your home network connection, eating up the bandwidth that you pay for, at least up until a SWAT team pays you a visit and shoots you in your bed for looking surprised.
• Any Network Attached Storage (ala 'Time Capsule') that you don't want to share with every person who visits and connects to your network should also have a password on it. No exceptions. Your nieces and nephews can be evil little buggers, and your family and friends can become nosey at 1:00am when they can't sleep.

Things You'll Need

> Some sort of 'Wi-Fi Hot Spot' or smart phone with Wi-Fi sharing capabilities enabled, with a cellular service plan that allows such functionality to work.

> A wireless router or network switch that connects to your home (or very small office) network.

> A Wireless Ethernet Bridge