Basic network troubleshooting
Because of the variety of network hardware, network configurations, operating systems, and setups, not all of the below information may apply to your network or operating system.
Note: We cannot assist you with network problems due to an unknown password or unknown ISP settings, as we have no method of verifying or determining this information.
Verify that the network adapter is properly installed and detected by the computer with no conflicts. In Microsoft Windows, open the Device Manager and verify there are no errors. "Network adapters" should be present for each network adapter installed in the computer, similar to the example on the right.
If conflicts exist or the network adapter is being detected as an "Other device", the network card has likely not been properly installed in the computer. Try letting Windows re-detect and install the network card by removing the network adapter and any other conflict devices from Device Manager and then rebooting the computer. If Windows re-detects the card but does not find the drivers, download the latest network card drivers from the computer manufacturer's website or the network card manufacturer's website.
- How do I remove a device in Windows Device Manager?
- Listing of network drivers and network card manufacturers.
If this is a wired network, verify that the network cable is properly connected and make sure the LEDs next to the network jack are properly illuminated. For example, a network card with a solid green LED or light usually indicates that the card is either connected or receiving a signal. If the green light is flashing, this is an indication of data being sent or received. The picture to the right is an example of a LAN port with two LED indicators next to the RJ-45 port. With this port, one LED will light up if connected properly and the other will flash when transmitting data.
If there are no lights or the lights are orange or red, the card may be bad, not connected properly, or may not be receiving a signal from the network. If you are on a small or local network and have the capability of checking a hub, switch, or router, verify that the cables are properly connected and that it has power. If after checking the connections, the LED indicators appear bad, the network adapter, port, or cable may be defective.
If you're using a laptop with a wireless network, look for the laptop's Wi-Fi button and make sure it is turned on. Many laptops have a Wi-Fi button that allows the wireless network to be turned on and off. The Wi-Fi button is often located just above the keyboard or on the front edge of the laptop, but it also may be integrated with a F key as well. The pictures to the right are examples of a Wi-Fi button and Wi-Fi indicator on a F key that are enabled.
If the button is turned on, make sure you're using the correct Wi-Fi hotspot by right-clicking on the Network icon in the Windows Notification Area and clicking "Connect to a network". Usually, the network with the strongest connection (the most bars) will be your wireless router.
Finally, when connecting to most wireless networks, you need to enter the proper SSID password to connect to the network. If the incorrect password has been entered, you will not be able to access the network.
To ping the card or the localhost, type either of the following commands:
Executing either of the above commands should get replies from the network card. If you receive an error, or the transmission fails, the network card is not physically installed into the computer correctly, has the incorrect or outdated drivers installed, or is defective.
Make sure the network card is physically installed in the computer correctly by removing it and re-inserting it again. Check the network card manufacturer's website for the latest drivers and install those drivers. If the network card is defective, it needs to be replaced.
Connect to the router
If all of the above steps have been checked, and your network has a router, make sure the computer can connect to the router by performing the below commands.
Determine the routers address
Using the ipconfig command (or ifconfig command for Linux), determine the router's address by looking at the Gateway address. Below are the steps for Microsoft Windows users. Linux users can substitute ipconfig for ifconfig.
- Open the Windows command line.
- At the command prompt, type ipconfig and press Enter. You should see output similar to the example below.
Ethernet adapter Local Area Connection:
Connection-specific DNS Suffix . : computerhope.com.
IP Address. . . . . . . . . . . . : 192.168.1.103
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1
The Default Gateway is the address of your router. Most home routers have a gateway address that starts with 192.168, like the address shown above. Assuming your gateway address is 192.168.1.1, attempt to ping the router to see if it can send and receive information by running the below command.
If you get replies back from the router, the connection between your router and computer are good, and you can skip to the next step.
If you do not receive any replies back from the router, either the router is not set up properly, or your connection between the router and the computer is not correct. Reset your router to make sure it is not a problem with your router by following the steps below.
- Turn off the power to the computer and leave it off.
- Unplug the power to your router and cable modem or DSL modem.
- Leave the power cables disconnected for 10-15 seconds and then plug in your modem and then your router again.
- Finally, turn on your computer again and repeat this step to see if you can ping your router.
If you have a wireless network and followed the above steps, but cannot ping the router, turn the computer off again and connect the computer to the router using a network cable instead of wirelessly. If a wire also does not work, contact the manufacturer of the router for additional support or replacement.
If your computer network utilizes a firewall, make sure all required ports are open, especially port 80, which is the HTTP port. If possible, disable the firewall software or disconnect the computer from the firewall to make sure it is not causing the network problems.
The Internet is not working
If you're able to ping the router, but are still unable to connect to the Internet, either your router is improperly configured, or the ISP is having issues.
Note: Some ISPs, such as Comcast, require special software to be installed. Make sure any software included with your Modem or other hardware has been installed on at least one computer if you are setting up a new Internet connection.
If your Internet has been working but recently stopped working, give it a few minutes to make sure it is not a temporary outage. If after waiting a few minutes, you still have problems, and you have not already disconnected the power to your router and modem, follow the steps below.
- Turn off the power to the computer and leave it off.
- Unplug the power cable to your router and cable modem or DSL modem.
- Leave the power cables disconnected for 10-15 seconds, plug in your modem again, and then plug in your router again.
- Finally, turn on your computer and see if you can ping your router.
If after following the above steps, the Internet is still not working, open the Windows command line and run the below command.
Running the above command should get a reply from Google. If you get a reply, this is an indication that the Internet is working, but you may be encountering a problem with the Internet browser you are using to browse the Internet. Try an alternative browser, such as Firefox or Chrome.
If you're getting no reply from Google, your router or modem is not reaching the Internet. If you have a router, make sure your router has DHCP enabled and that the WAN or Gateway address is the proper ISP address.
Finally, if trying the above steps has not helped, contact your ISP to make sure there is no problem on their end and to assist you further with any special configurations.
Another method of determining network issues is to use the tracert command if you are a Windows user or the traceroute command if you are a Linux or Unix variant user. This command gives you an overview of each of the devices (routers) a packet travels (hops) over a network. It can also give you an idea of where a problem exists in your network or outside of your network.
To use this command, you must be at the command line and type one of the below commands, depending on your operating system.
If successful, you should begin to see each hop between the computer and network devices. When the connection fails, determine what device is causing the issue by reviewing the traceroute listing.