Troubleshooting a Slow Network Connection
Great tips on network troubleshooting from the CompTia IT Pro networking blog.
- Problem at the physical layer: Many times, I’ve found that slow networks occur because of some sort of problem with a particular device(e.g., a cable modem or a switch), or even the network cable itself. If you’re using a cable modem, try restarting it before contacting anyone or going any further. Check to see that all physical connections are sound; a loose wire can mimic other problems. Start here, and you’ll be able to move forward with confidence. Additional issues can include firmware update problems. One time, I had a cable modem that simply “bricked” because my ISP’s automatic update procedure failed. Other times, I’ve found that a cable modem hasn’t fully installed a firmware update, causing slowness. Sometimes you need to get a new modem; other times, you simply need to either complete the firmware update or simply restart it.
- Network service problem: Start with diagnosing DNS issues. We all know what a completely failed DNS server can do to you. But have you ever been in a situation where you go to a familiar URL (e.g., http://www.bbc.co.uk) and then the browser tells you that it is “looking up” or “resolving” the URL? It will eventually find the URL and resolve it for you. This problem is likely due to a problem with your DNS server of that of your ISP. Restart the service if it’s your own; if you’re using a DNS server provided by the ISP, either switch to a backup server or inform them that there’s a problem. As with the previous piece of advice, actually restarting your computer can help resolve this issue, too. Additional services to consider include domain controllers, Microsoft networking / Samba servers, and torrent services. In some cases, network traffic will run slow because your network isn’t configured to prioritize certain traffic types. In other cases, you’ll need to set up port forwarding so that certain traffic types on your network will be properly forwarded by your router. For those of you interested in how an enterprise network prioritizes traffic, check out the following link about QoS.
- Computing device issue: I once had a friend of mine who was convinced that his company’s ISP was at fault for slow network speeds. It turned out that his system was infested with spyware, causing a serious slowdown in networking. Removing the spyware solved the problem. In another case, the computing device had a problem because it had the wrong software driver installed for the network card. Resolving that issue resolved the slowdown issue nicely.
Head to the source to find out some other things to investigate when dealing with a slow network connection.
- FBI Report on DNSChanger Malware (bespacific.com)
- Google Public DNS serves 70 billion daily requests (slashgear.com)
Posted on February 15, 2012, in Internet, IT Support, Network Administration, Tech Tips and tagged CompTIA, Domain Name System, Internet service provider, Local area network, Network interface controller, Network performance, Uniform Resource Locator. Bookmark the permalink. Comments Off.