Ubuntu: Connecting to a Wireless Network
A wireless (Wi-Fi) network is, as its name suggests, a network that does away with cabling and uses radio frequencies to communicate. It's more common for notebooks and handheld computers to use wireless connections, but some desktop computers also do. Indeed, it's increasingly the case that many workplaces are switching to wireless networking,eschewing old-fashioned, cable-based networking.
NOTE: Slowly but surely. Wi-Fi is replacing wired Ethernet networks, but there are many situations in which Wi-Fi networks are impractical or simply undesirable. For example, the metal infrastructure in some buildings means the signal becomes unreliable. Wi-Fi is also considered too insecure for some companies. The Wi-Fi signal often spreads to the street outside the building. Although such transmissions are nearly always secured, Wi-Fi security implementations have been broken, although WPA2 is considered secure right now. Ethernet might be considered old technology, but trying to steal data from physical cables is an order of magnitude more difficult, to the point of being practically impossible.
Notebooks and PDAs typically use built-in wireless network devices, with an invisible antenna built into the case. However, some notebooks might use PCMCIA cards, which will have an external square antenna, and some desktop computers might use PCI-based wireless cards, which have external rubber/plastic antennas, in the style of old cell phones.
Ubuntu includes support for most wireless network devices. However, it's possible to use Windows wireless network device drivers for unsupported hardware. Also, sometimes Ubuntu appears to support a wireless network device, in that it identifies it and lets you configure it, but you might find that it simply doesn’t work (or works very badly, perhaps with an intermittent connection). In this situation, you can also try installing Windows drivers.
Connecting to a wireless network device is easy with NetworkManager. Just click the NetworkManager icon, and you will see the available Wi-Fi networks in the Wireless Network list. Networks protected with WEP/WPA will have an icon of a padlock. Those that are "open" will not have this icon.
You might see many Wi-Fi networks listed, depending on your location. The wireless base stations are identified by their Service Set Identifier (SSID) or sometimes ESSID, with E standing for Extended.
If the SSID you would like to connect to is not listed by NetworkManager, it could mean that your wireless base station isn’t set to broadcast its SSID or, worse, Ubuntu's Wi-Fi drivers aren't functioning correctly. If it’s the former, all you need to do is right-click the NetworkManager icon and select Connect to Other Wireless Network. Then, in the new dialog box, type the SSID under Network Name, set Wireless Security to none or the appropriate security type, fill in the other information depending on the type of wireless security you selected, and click Connect. If it’s the latter, you may need to use a Windows driver, as described in the next section.
To connect to a Wi-Fi network, select the wireless base station you wish to connect to in the list. If it isn't protected by WEP/WPA, you will be connected to it automatically.
If the Wi-Fi network you wish to connect to is protected with WEP or WPA, a dialog box will appear, prompting you for the password/passphrase. In the Wireless Security field, make sure the correct type of security for the wireless network is selected - don't assume it's automatically correct! By default, the password/passphrase is obfuscated by circle characters so that anyone looking over your shoulder can’t see what you're typing. If it helps (and if your shoulder is clear!), check the Show Password box. This can really handy when you’re typing a particularly long passphrase.
NOTE: WEP keys come in either hexadecimal (hex) or plain text (passphrase) varieties. Hex keys look similar to this in their 128-bit form: CB4C4189B1861E19BC9A9BDA59. In their 64-bit form, they will be shorter and may look similar to 4D9ED51E23. A passphrase will take the form of a single short sentence. In home and office environments, WPA networks are usually protected with passphrases. In larger corporate or academic environments, you might find the network is protected with a WPA certificate.
When you're finished, click the Connect button. You should see the NetworkManager icon start to animate as the program attempts to connect and find an IP address. After a few seconds, when the animation finishes and the icon switches to display signal bars, you should find yourself online.
If your computer doesn't seem to connect, try rebooting. If the hardware doesn't work after this, it might be that the drivers Ubuntu installed by default are incompatible with your network device. In this case, you can try using a Windows wireless network device driver.
Should you find yourself in the unusual situation of needing to specify the IP address, subnet mask, and gateway for a wireless connection, you can do so using the manual configuration mode of NetworkManager. Simply follow the instructions in that section, but select the Wireless Connection entry in the list, rather than Wired Connection. In the dialog box that appears, you'll see additional areas where you can enter your SSID and WEP/WPA protection details.
Tips:
TIP: If you are not offered any wireless networks at all, ensure the wireless hardware is switched on. Some notebooks have a keyboard combination to turn it off to save battery power. Additionally, try right-clicking the NetworkManager icon and ensuring that the wireless networking hardware is activated.
Tags: pci,wireless,wpa,wep,wifi,drivers
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