Tech Magazine

Basic Network Diagnostic Tips and Tricks

Posted on the 04 September 2011 by Nerdywerds @NerdyWerds
You don't have to be a geek to fix you internet connection problems

We've all dealt with internet connectivity problems. They seemingly happen for no good reason, and right in the middle of me doing something. I've seen about 3 distinct methods for handling these problems; some people go fetal until it magically fixes itself, some people call their internet service provider and others call me. Needless to say, it's a bit inconvenient to get in touch with me, especially if you don't live within 5 miles of my home. So I propose that we spend a few minutes together and I'll just tell you the basic strategies I employ to fix these problems. That way, if after reading this article you can't fix it, you'll know not to call me because I probably can't either.

I'm going to assume, for the sake of this article, that you have had a working internet connection at one point. If you're looking for a guide to setting your internet, check out this guide to home networking .

First rule of tech support, always tell the customer to turn off their computer. This usually doesn't fix the problem, but it is almost always the thing tech support will tell you to do. Now that that's out of the way, let's get down to basics. If you are in that group of people that call your ISP looking for help, you'll know the first thing they tell you to do, should you actually get through, is to disconnect your router or switch. You'll need to locate the cable between computer and the router, and disconnect the router end. Now, plug that bad boy into your modem. It may not be necessary, but remove the power cord from the modem for a slow ten count. Now reconnect the power cord and let the modem fully power up, about a minute to be sure. Try connecting to the internet again. If you're back up and running, you can rule out the modem or your ISP as the problem. If you're not, this is when you do need to call your ISP because odds are your problem isn't within your control. You should check the connections before calling however. Make sure your cable is well secured to to the wall and your modem.

Now that we've ruled out the modem, let's step back to the router or switch. If you didn't already reconnect everything the way it was before, go ahead and take the cable from the back of the modem and reinsert it to the router. Then reconnect your modem and pull the plug from both for a good ten seconds. Then reconnect your modem and router/switch. Give it about a minute and pray to whomever you do and hope this works. If not, fight the urge to go fetal. We will get through this. Next, we're going to try connecting to the router/switch via the browser. Different brands use different addresses, so you'll need to consult your network devices documentation to know what to try. For me, and many Linksys products, the IP address is "". If you can bring up your device's setup page, congrats, your router isn't the problem.

This next step may, and should, make you feel a bit nerdy. On a Windows machine, go to the start menu and type "cmd" in the search bar then press enter. This launches the command prompt. Hardcore users love this tool for it's speed and power, but this isn't the place to discuss the prompt, that's another article for a different day. If you own a Mac or Linux machine, just open a terminal and you are ready to rock. We are going to "ping" a few different places. A ping is kind of like sonar; you send some data out and hope that it bounces back from the destination. We are first going to ping Google. So for Windows, type in "ping -n 5", for Mac or Linux type "ping -c 5". This tells your computer to send 5 pings to Depending on the status of your network, you'll be waiting for a few seconds to a minute. After all is said and done, you'll get a "Ping statistics" report. Look at the "Packets" part. Our goal is to send 5 packets and receive 5 packets. Any packet loss means you're connection isn't running at full bore. If you have a 0% packet loss, you should try getting on the internet again; you may have experience a very momentary internet loss; these do happen unfortunately.

If you get a message about not being able to resolve to host, or not able to connect to host, or anything that would imply there is a problem with the host, you may a DNS issue. The domain name system, or DNS, is used by the internet to interpret IP addresses. Every website has an IP address. For instance, go to "". You'll see that this takes you to Google. The DNS links that ip address and, so when you type in, your browser consults the DNS to know what ip address to go to. If there is a problem with your DNS server, your browser will not know how to reach the sites you're looking for. If you've gotten any indication that your DNS server may be the problem, we do have a few solutions. We're first going to try and flush your DNS cache. In Windows, open your command prompt again and type "ipconfig /flushdns". This will clear the memory of DNS and force the browser to retry the DNS servers. In Mac OSX 10.5 and above, type "dscacheutil -flushcache" in your terminal. In Mac OSX 10.4 and lower, type "lookupd -flushcache". Try pinging again. If you get no dropped packets, you had a bit of a DNS problem and all is well now. If not, let's keep on plugging away.

We're going to try pinging your DNS servers. First, we need to find what they are. Go back to your command prompt or terminal window. For Windows, type "ipconfig /all". Find your "DNS Servers" records and write them down. For Mac, type "nslookup" and note the results. Now try to ping these addresses. If you don't drop any packets, it would appear your DNS server isn't the problem. Or at least it tells you that it's working.

We're next going to try changing the DNS server. Sometimes and ISP's DNS servers go down, or don't work as well as hoped for. We're going to change your DNS server to use the OpenDNS instead. For Windows, go to "Control Panel -> Network and Sharing Center -> Change Adapter Settings" Then right click on the network connection you use and select properties. Select "Internet Protocol Version 4" and click properties. Check the button next to "Use the following DNS server addresses" and enter "" in the first DNS field, and in the second, enter "". Click OK and try pinging again. For Mac users, open "System Preferences" then click "network". Then double click the connection you want to work with. On the connection properties window, click the DNS tab. Use + or - to add or remove a DNS server. You'll want to add the same DNS servers as your Windows friends did. You'll also need to ping Google again.

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