Troubleshooting internet connectivity problems.



13 01 2009

nic

Have you ever opened up your web browser and seen the “The page cannot be displayed” or “unable to connect to server” message? Having internet connectivity problems can be frustrating. Here is a guide to help you get through them.


Page cannot be displayed

Power

Make sure that your router, modem, and any other pieces of network equipment have power. This can be done by simply look at each device to see if the LEDs are on.

Connections

Check that all cables are tightly connected in the proper place.

Power cycling

Power cycling your equipment can fix many internet problems. if you don’t get anything right away, wait a couple of minutes and try again.

ISP

At this point, if you are not successful you may want to contact your ISP to confirm that there’s not a service outage in your area or a billing issue on your account. I occasionally work for a helpdesk that provides support to over 250 remote offices with independent internet connections and more than half of the connectivity issue calls that I receive are resolved by these steps (they usually forget to pay their internet bill).

Additional steps

You can try these additional steps to continue the troubleshooting. We want to work from the inside out so we will check the computer > router > modem > internet > DNS.

IPCONFIG

To see if you have an IP address, open a command prompt by clicking start > Run > in the run box type CMD and press enter.

When the black window with the blinking cursor comes up type IPCONFIG, this will display the IP information.

You should see something similar to the following:

Ethernet adapter Local Area Connection:

IP Address. . . . . . . . . . . . : 192.168.1.100
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.1.1

It may have slightly different numbers, but if you see something like this, then you have an IP address.

Ping tests

You can use pingwhich is a network connectivity test.
In the command prompt type PING then the Default gateway address that was found in the IPCONFIG section above.

IE

PING 192.168.1.1

If you see,

“Reply from 192.168.1.1: bytes=32 time<1ms TTL=150"

Then you know your computer is communicating with your router and you can move on to the next step.

The next step would be to ping modem if you know its address or know how to get it through your router or to ping a host on the internet.

You could try PING 4.2.2.2 which is a DNS server belonging to Level3 Communications.

If you see reply from 4.2.2.2: bytes=32 time=23ms TTL=244, then you are connected to the internet.

DNS

Even though you get a reply from 4.2.2.2, you still may not be able to get to webpages or services. If this is the case, then you may have a DNS problem. DNS translates names like google.com to IP addresses like 74.125.45.100.

Troubleshooting DNS problems.

To see if you have a DNS problem, try pinging a host name on the internet. For example you could PING google.com.

ping

If you see “Ping request could not find host google.com. Please check the name and try again.”

Then you have a DNS problem which can be troubleshot by using different DNS servers or the NSLOOKUP command.

Your ISP may be able to help you with this troubleshooting process.

Good luck!

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One response to “Troubleshooting internet connectivity problems.”

19 06 2010
Suranga (05:45:46) :

When I tried to access to “Facebook” my Windows Explorer gets automatically shut down.

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