Amy and I both travel with our laptops.  Lately I’ve been using my Verizon EVDO card everywhere.  It’s awesome.  I was thinking about getting Amy one when Ross suggested that she could simply buddy breathe off of mine.  We tried it for a week when we were in Miami – it worked flawlessly.  It’s a little tricky (e.g. “non-obvious”) to set up – the directions are below. 

There are two laptops.  The first – the “Master” (e.g. mine) is connected to the Internet.  In my case, it was connected via EVDO, but it could be WiFi or via a physical ethernet connection.  The second – the “Slave” (e.g. Amy’s) connects to the Master via a WiFi connection. 

Configure The Master Laptop

• Right click “My Network Places” – “Properties”
• Right click on “Wireless” (or whatever the name of your WiFi card) and choose “Properties”
• Click the “Wireless Networks” tab
• Click “Advanced”
• Select “Computer-to-Computer….” – Click “Close”
• Click “General” tab
• Select “TCP/IP” and click “Properties”
• For IP Information: (you must use a static address here) “Use the following…” “IP: 192.168.201.1″ “Mask: 255.255.255.0″ “Gateway: BLANK”
• Click “Ok”
• Click “Close”
• Connect to the Internet connection (EVDO, wireless, or wired) 

Configure The Slave Laptop

• Right click “My Network Places” – “Properties”
• Right click on “Wireless” and choose “Properties”
• Click the “Wireless Networks” tab
• Click “Advanced”
• Select “Computer-to-Computer….” – Click “Close”
• Click “General” tab
• Select “TCP/IP” and click “Properties”
• For IP Information: “Use the following…” “IP: 192.168.201.2″ “Mask: 255.255.255.0″ “Gateway: 192.168.201.1″ “DNS: 66.174.92.14″ (you only need 1)
• Click “Ok”
• Click “Close”

That should do it.  Both computers should be able to access the Internet (assuming the Master is connected to the Internet.) 

While this works nicely when you want to share, it’s no so nice when you want to go back to your primary connection.  On both the Master and the Slave, you’ll need to undo this change.  If you don’t do this when you’re done you’ll effectively be cutting yourself off from WiFi.

Undoing Buddy Breathing

• Right click “My Network Places” – “Properties”
• Right click on “Wireless” and choose “Properties”
• Click the “Wireless Networks” tab
• Click “Advanced”
• Select “Any available network” – Click “Close”
• Click “General” tab
• Select “TCP/IP” and click “Properties”
• Set both IP and DNS to “Obtain Automatically”
• Click “Ok”
• Click “Close”
• Right click on “Wireless” and choose “View available wireless networks”
• Select the network and connect

This assumes you are using DHCP to connect.  If you settings – prior to making the buddy breathing change are for a static connection (e.g. you don’t “Obtain Automatically” the IP and DNS) – you need to put the static IP settings in.