Fix the Internet Connection

"Networking" by pobre.ch @Flickr

“Networking” by pobre.ch @Flickr

The Internet probably isn’t broken; chances are something is wrong a lot closer to home. So before panicking, start by trying to identify the problem.

Quick Links:

Physical

It might sound obvious, but as every networking student learns, it is important to start with the physical connection; wired or wireless – because if there is no physical connection between your machine and the rest of the network nothing else you do can ever matter. You may have to get up off your seat.

A physical connection problem will most likely show itself as red x over the network connection icon in Windows.

  • From the Windows command-line (run command at the Windows menu) try the command getmac – a return of “media disconnected” is an indicator that something is amiss. Whereas if everything is connected it will return the MAC address (network device serial number) for each connection on your machine.
  • Check that the cables are in. You should see flashing lights to indicate a working connection at the point where the cable connects to your computer.
  • Is WiFi turned on in your computer?
  • Is the wireless router turned on?

Local Network

If everything is connected as it should be and you still have problems the next step is to check the network settings. It certainly helps if you know what network you are supposed to be on but even so you can probably work things out from here.

  • From the Windows command-line (run command at the Windows menu) try the command ipconfig (or ifconfig in Linux). This should reveal your device’s network IP addresses for each network it has joined. It looks like four decimal numbers separated by dots, e.g. 192.168.1.2, 172.16.0.2 or 10.0.0.2.
    • We expect that you should have at least one IP address starting with either 192.168, 172, or 10.
    • The address starting in 127 is just a reference to your own machine. It is normal, but is not part of troubleshooting your Internet connection.
    • An IP address starting in 169.254 indicates that your machine tried to get configured by a router but failed. Check the connection to the router and either restart your machine, disconnect and reconnect the cable/connection, or run the command ipconfig /release followed by ipconfig /renew.
    • This address is not the same as your router’s external address on the Internet (that can only be found from an external service such as ipchicken.com).
  • Part of the output from ipconfig included a “gateway” address. This is the address of your router. (In Linux you will need to run route to establish the gateway address.)
    • Next test to see if you can contact your router. The test command is ping (like the submarine sonar signal). To test, for example, the link to a router numbered 192.168.1.1, the command is ping 192.168.1.1. If successful we can discount any problems with the local network connection; otherwise we can be certain that there is a local problem with the connection that needs to be fixed and pinging successfully before anything else is tried.

Internet

If you have a connection to the router then the next step is to check your Internet connection.

  • First check the connection to a known IP address on the Internet: ping 8.8.8.8 which is the address of one of Google’s servers and should always be available and answering. If you get a ping back from 8.8.8.8 then you have a connection to the Internet.
  • Second, check to see if you can ping a named address on the Internet: ping google.com. If you get a response then you are properly connected. If you fail to get a response then look to your DNS (domain name system) settings – you have access to the Internet but the translation from names to numbers isn’t available. Normally your DNS settings are set automatically in your TCP/IP settings but if necessary you can enter your own. Follow the link to your connection in the “Network and Sharing Center”, click “proprieties”, double-click “Internet Protocol Version 4” to find the DNS settings. You can try either the address of your router, the DNS addresses given to you by your ISP, if you know them, or Google’s public DNS servers: 8.8.8.8 and 8.8.4.4 (more information at developers.google.com/speed/public-dns).

Application

If everything else is testing OK, then it is time to check out your application settings. Try a difficult application or browser: Chrome, Firefox, Internet Explorer.

Of course the remote service could actually be down and the problem wasn’t yours to begin with. Make doubly sure you have the correct address and check the service on http://downforeveryoneorjustme.com – it may not just be you.

Connection Speed

A slow connection might be just as bad as a broken connection at times. But before complaining, get the facts:

  • Although the internal network connection speed may also need checking (follow the link to your connection in the “Network and Sharing Center” in Windows to read the maximum line speed; most likely 1Gbps) it is unlikely to have an overall impact on your experienced Internet speed.
  • To check the current speed of your connection to the Internet use a service such as speedtest.net or speedof.me. Test, if possible, with no other applications or users on your local network using the Internet. A comparison of download, upload (normally much slower) and ping speeds over time can help you identify and quantify speed issues.