How to Troubleshoot Connection Issues on Public Wi-Fi Networks


Larry writes: While traveling recently I attempted to connect to an airport’s free Wi-Fi on my MacBook Pro running OS 10.7 Lion. Although I could connect to the same network on my iPhone, my MacBook Pro would not connect. Strangely, when I rebooted the MacBook Pro into Windows 7 via Boot Camp, the connection worked fine.

What’s going on with OS X and this Wi-Fi network?


Mac OS X Wi-Fi Troubleshooting

All things being equal, and especially considering that the same hardware was able to connect to the network using Windows, OS X on your MacBook Pro should have no problem connecting to this network. All things are rarely equal, however, so here are some troubleshooting steps you can try if your Mac is having difficulty connecting with, or communicating with the internet from, a wireless network.

First, change, or add, a DHCP Client ID. This is usually not necessary but some networks require it. Go to System Preferences > Network > Wi-Fi > Advanced. Head over to the Hardware tab and select and copy your MAC Address (a series of letters and numbers separated by colons).

Now go to the the TCP/IP tab and paste your MAC address into the DHCP Client ID box. Press OK and try to disconnect and then reconnect to the network.

If that alone doesn’t work, go back to System Preferences > Network > Wi-Fi > Advanced > TCP/IP and click the “Renew DHCP Lease” button. If your difficulties are caused by an expired DHCP-provided IP address, this should solve them.

Mac OS X Wi-Fi TroubleshootingEnter a DHCP Client ID and Renew your DHCP Lease

Finally, if you’re actually connected to the network but when you load Safari nothing happens (or you receive a “Browser/Platform not supported” type of message) it may mean that the wireless network has been configured to block Mac users.

Thankfully, there’s a way to trick the network into thinking that your Mac is actually a Windows-based platform. First, go to Safari > Preferences > Advanced and check the box “Show Develop menu in menu bar.” This will place a new “Develop” menu in Safari’s menu bar in between “Bookmarks” and “Window.”

Safari's Develop Menu User AgentsThe Safari Develop Menu’s User Agents List. Select a Windows-Based Browser

Select “Develop” from the menu bar, then “User Agent.” You’ll be presented with a list of different Mac and Windows browsers that you can have Safari masquerade as. Select the most recent version of Internet Explorer or Firefox for Windows and then attempt to reconnect to the wireless network. Safari will tell the network that it is actually a Windows browser and, if the problem was due to artificially blocking Macs, your browser should load the network’s sign-on page without issue.


[Teaser graphic element via Shutterstock]