How to fix your Internet connection in Ubuntu Linux
Ubuntu’s included NetworkManager software aims to make your network connections “just work.” Nevertheless, sometimes thing go awry. There are times you have to adjust or change your connection settings, especially when using a laptop—just like in Windows.
Luckily, you won’t have to pull up the terminal and type any arcane commands to make your Internet connection work.
Check the basics first
Before you blame Ubuntu, try connecting to the Internet on other devices. If they're experiencing the same problem, it isn’t with Ubuntu—it’s with something else. For example, you may need to reboot your router, modem, or both. It’s always worth checking these fundamentals before delving into further troubleshooting.
Some laptops have hardware switches that can be toggled to quickly enable or disable Wi-Fi. If your Wi-Fi doesn’t seem to be working at all, check your laptop's hardware Wi-Fi switch.
If you’re using a wired connection, ensure the ethernet cable is plugged firmly into both the computer’s ethernet port and the router’s ethernet port. Sure, this may seem a bit obvious, but it’s easy to miss a bumped switch or loose cable.
To fix signal strength problems with Wi-Fi networks, arrange your router, computer, and other objects in your house for the best possible Wi-Fi signal strength.
Configure your connection settings in NetworkManager
NetworkManager connects to Wi-Fi networks and automatically configures wired network connections when you plug in an ethernet cable. Before NetworkManager, you’d have to do this with terminal commands.
If something isn’t working properly, you may still have to configure NetworkManager. Click the network connection or Wi-Fi icon on the panel at the top-right corner of your screen to access the NetworkManager menu, then choose a network. If you need to view information about your connection for troubleshooting purposes—your computer’s IP address, for example—click Connection Information.
If your local network connection isn’t working, ensure the Enable Networking and Enable Wi-Fi options are selected here in the menu. These options let you quickly disable and enable your connections, which is useful for putting your laptop into airplane mode. If you accidentally disabled either, you won’t have an Internet connection until you re-enable them.
Configure your connections by clicking Edit Connections. You’ll see a window with one or more connections, depending on how many network adapters you have in your computer. Select a connection and click Edit to modify its settings.
Ensure the ‘Automatically connect to this network when it is available’ option is enabled on the General tab. If it’s disabled, NetworkManager won’t automatically connect to a wired or wireless network when you boot your computer.
NetworkManager uses Dynamic Host Configuration Protocol (DHCP) by default, so your computer will attempt to get connection settings—IP address, DNS servers, and default gateway—automatically from your router or Internet service provider.
For networks that require a static IP configuration, you’ll need to visit either the IPv4 Settings or the IPv6 Settings pane and select the “Manual” method. (If you’re not sure which you’re using, you’re probably still using IPv4.) Enter the details your connection requires here—your ISP or network administrator can tell you what to enter if you don't know.
If, for some reason, your network only allows devices with a specific MAC address to connect, click the ethernet tab and enter that information into the 'Cloned MAC address' box.
Keep reading for more on checking Wi-Fi drivers and wielding diagnostic tools.