What to do when your home wifi stops working and your broadband provider can’t fix it

People tend to take their home wifi for granted, like their electricity supply: it’s just supposed to be on. But unlike your power, if your wifi stops working, too often it’s up to YOU to diagnose and fix it.

I work at home and depend on broadband internet to make my living. This week I lost about two full working days because my broadband went out. My internet service provider (ISP), Comcast, was unable to get it working or even steer me in a useful direction, despite keeping me on the phone for hours and running lots of tests of the connection between their equipment and my equipment.

Were I not lucky enough to know a programmer with lots of networking experience who could spend time helping me investigate other possible points of failure, I’d be out of luck for home wifi right now — which would severely hinder my business and life.

Here’s what happened with my home wifi, and how I fixed it. Also here’s why ISPs need to do a much better job of helping residential customers diagnose possible network problems that lie beyond the narrow scope of the wires and modems they sell…


Unless there is a local internet outage in your neighborhood, or there’s an apparent problem with your line connection or cable/DSL modem, your ISP probably will be no help on diagnosing and fixing your problem. They won’t help you investigate other avenues beyond the narrow scope of what they’re selling you.

Unfortunately, wifi has many potential points of failure — most of which are unfamiliar territory to the typical consumer. Your home wifi also depends on internet equipment like domain name servers, and on local conditions like wifi interference. It takes some knowledge and skill to diagnose and fix these conditions.

Ever since I moved into an apartment building in Oakland, CA last summer and signed up for Comcast’s cable modem broadband service (now Xfinity), my connection has been a bit flaky. My Mac laptop would suddenly either lose its connection to the wifi router, or my home wifi network would be working but I wouldn’t be able to access any web sites or online services.

Sometimes resetting the router and modem would fix this. Other times the service would just as mysteriously reappear a half hour or so later. And sometimes, I’d call Comcast and learn that they were having an outage that affected my area.

This week, the problem was different: The service never came back on. I called Comcast, and they verified that there was no local outage. I then spent nearly two hours on the phone with their tech support running through various fixes that basically reset my home equipment (my Mac laptop and its built-in Airport wireless modem, the Comcast cable modem, and my Apple Airport Express wifi router) in various combinations.

Nothing worked. Especially odd was that my laptop was repeatedly unable to show a valid IP address.

So I packed up my laptop and headed off to a local coffee shop with free wifi to get some work done. My laptop accessed that network immediately and with no problems, so I knew the problem was not my computer.

Even though the Comcast tech saw no problems with my modem, he suggested that if my computer worked fine elsewhere, it wouldn’t hurt to go to the local Comcast service center to exchange my modem for a new one. Comcast exchanged my modem at no charge.

When I got home later that night, I connected and activated the new modem — and boom, I was online just fine. No problem. I went to bed relieved, thinking I’d fixed the problem.


The next day I was online just fine until about the middle of the afternoon. Then, suddenly, I lost my internet connection again: first I was unable to hit any sites, and then my laptop stopped being able to connect to my home wifi at all.

I was on the phone to Comcast again, and again they ran me through the same diagnostics. The problem was weird: everything seemed to be working, but I was still failing to obtain a valid IP address.

The end result: Comcast said, “There’s nothing we can do here. We can send a technician to your house, but if the problem is not our equipment, you’d have to pay for that visit.”

I understand their perspective, but that is a really shitty approach to customer service. Comcast could have — and should have — offered further resources for self-diagnosis, but they didn’t.

At my wits’ end and not knowing what else to do, I scheduled a technician visit for the following day. I was pretty angry.

Then I called my friend Tom Vilot, an actor and software developer. He saved my butt.


Tom had me connect my laptop directly to my cable modem via ethernet, and turn off the built-in Airport modem in my laptop. He then walked me through opening a terminal window (under “utilities” in my Mac’s applications menu) and we ran several “ping” tests using UNIX commands to determine whether I was in fact communicating with the internet.

From this he determined that at least part of my problem was related to Comcast’s domain name servers (DNS) — a core part of the internet that translates human-readable domain names into computer-readable numeric IP addresses.

“I’ve seen this before, Comcast’s DNS is really flaky,” said Tom. “So Comcast is definitely part of the problem here, but not in a way that their tech support staff can do anything about. That’s why they didn’t mention it.”

Tom then directed me to go into my Mac’s system preferences. Under “network” he had me select the active ethernet connection and then click “advanced.” Then, under the DNS tab he had me enter the address for one of Google’s own domain name servers:

Once I applied that setting change, I was suddenly able to access web sites and other online services again. So the first part of my problem was solved.

“Google’s DNS is much, much more reliable than Comcast’s. It needs to be,” said Tom.

But Tom cautioned me that a direct ethernet connection to my cable modem is not a safe option. It’ll suffice in an emergency — but there are a lot of port sniffers out there looking for unprotected access to computers. I don’t want my computer to get hacked. Apple wifi routers provide a fair amount of security against such invasions, so I knew I needed a functioning home wifi network.


Next, Tom had me unplug the power from my cable modem, unplug my Airport Express wifi router, reconnect the ethernet cable from the modem to the router (what you normally need to do to have a local wifi network), and then plug both devices back in to power. For good measure, I also restarted my laptop. Then I turned my laptop’s Airport modem back on.

My laptop was unable to connect to my local wifi network. It would see the network on the list of available networks, but couldn’t connect.

At this point Tom speculated that I might be getting wifi interference from someone else’s router in my building. he explained that Apple’s Airport Express routers — and most other basic router models — operate only on a handful of common wifi “channels” in the 2.5 Ghz spectrum band. In a setting like an apartment building, where many occupants are likely to have their own wifi networks, wifi interference can become a problem.

Tom explained that the Airport Express modem automatically picks which wifi channel it will use to broadcast your home wifi network. This device only has one ethernet port, so it offers no easy access to diagnostics related to possible interference, and it’s difficult to get it to change channels.

Apple’s higher-end router, the Airport Extreme, has four Ethernet ports and access to a far wider range of wifi channels. It’s not cheap (almost $200 with tax), but it does give you more options to diagnose and circumvent wifi signal interference.

Since home wifi is a necessity, not a luxury, for me, I hopped on my bike and went to the nearest Apple Store, where I purchased an Airport Extreme.

When I got home, I called Tom again. (I am so grateful he was available to me that evening!) I hooked up the new router to my cable modem, recreated my home wifi network (password protected, of course), and boom! I was online again, no problem.

At that point I called Comcast and canceled the technician visit.

Tom then had me download the free application KISmac, which provides additional information about available local wifi networks.

I installed and launched KISmac. This program showed me which local networks were available and what channels they were using. I could see about 20 local networks, all on channels 2,4,6,7, and 9 (in the 2.5 GHz spectrum band). This indicates a situation where wifi interference is more likely to occur.

My network, with its new souped-up router, was the only network using channel 149 — in the 5 GHz spectrum band.

Tom notes: “It’s worth running KisMAC every once in a while to scan around and see what channels are being used. What I usually do is sort by signal ‘Avg.’ My wifi will, of course, show up at the top or near the top, since it’s got the strongest local signal as far as my computer is concerned.

“I then look at the other wifi stations that are near mine in signal strength (since they are obviously the ones most likely to interfere with mine). If they are on channels sufficiently far away from mine, I don’t need to change anything.

“But if I am on channel 7 and the neighbor with the nearest wifi is on 6, I will reconfigure the router to use channel 1 or 12. Similarly, if the next-strongest local network is on channel 11 and I’m on 7, I’m probably ok — but I might switch to channel 1 to be safer.”


1. If you use home wifi, you need to learn a bit about how the internet works. It’s not like electricity, where you can mostly afford to not understand how the power grid works. Your ISP is only part of what gets you online.

Your ISP is responsible only for the cable/DSL “wired” connection to your home, and (usually) the modem device which receives that signal. What happens with your wifi router and computer(s) is your responsibility. These devices can fail as well, but your ISP can’t test them for you.

Be aware of other potential points of failure — especially DNS problems and wifi interference.

2. Know how to manually specify the DNS your computer uses. Two Google public DNS servers that I now have programmed into my network preferences panel are: and Here are Google’s instructions for accessing these servers from your computer.

ArsTechnica cautions that Google’s Public DNS is not the right solution for everyone. Fortunately, there are many other public DNS servers, and some commercial services like Open DNS.

3. If you live near lots of other wifi networks, get a higher-end wifi router. This costs more, but it’s more likely to keep you online since it gives you more options to diagnose and circumvent local wifi interference. This is especially true for apartment dwellers, but also can be the case in crowded neighborhoods.

4. Don’t expect your broadband provider’s tech support to help. It’s worth running through their diagnostics because their equipment and systems can — and do — fail. But when they reach the end of what they can help you check, you need to know what else to check and do.

That’s why I took the time to write this post. Comcast gave me no hints or indications of how I might continue to track down this problem. If I didn’t have an ubergeeky friend to call who happened to have the time to help me, I would be in serious trouble right now.

There is a lot of information available about these problems online, but it’s REALLY geeky and most people wouldn’t know how to begin to search for solutions.


I wish broadband providers would teach their tech support staff how to explain to non-technical customers additional possible points of failure in home wifi networks — and then offer a resource guide for further diagnosis.

Such a guide would cover the kinds of topics I’ve covered in this post. It should be available with instructions for Mac and PC systems, and in multiple languages. Where possible it should recommend specific devices (such as routers) and tools (such as the KISmac application) that might help solve the problem.

Broadband providers could easily get this information to customers whose home networks aren’t working. Here’s how:

  1. Provide a printed resource guide at installation. Cable and DSL providers have to send out a technician to activate service and install the customer’s modem. They should take that opportunity to explain that their equipment is only part of the broadband ecosystem, and offer a relevant guide for diagnosing problems that might fall outside their area of responsibility. They should encourage customers to keep this guide in a place where they don’t lose it.
  2. If the customer has a smartphone, they could send a text message with a link to the appropriate version of the guide — or at least post this info in an obvious place on their mobile site (one that doesn’t require too much searching or clicking around, which is challenging even on a smartphone).
  3. If the customer has an e-mail-enabled feature phone, they could e-mail the guide in text form to the customer’s phone-accessible e-mail address.
  4. Fax or e-mail to a secondary contact. Most people know someone nearby who does have internet access, or a local copy shop or other place where they could receive a fax. This alternate contact could receive the document on behalf of the customer and print it out. Customers should be able to specify this alternate contact on the spot, during a problem, so they’re directing it to the most easily available contact at that moment.
  5. Snail-mail a printed copy. This is a last-ditch solution since it would take the a day or two to arrive, but it would work.
  6. Provide a call-in Q&A service. Some of this could be automated, and maybe make it available for a low fee. But give customers who have already determined that the problem is not the ISP someone they can talk to who can actually try to help them. Don’t just leave them stranded.


Home broadband service is increasingly being recognized as crucial infrastructure, since it’s the best (and sometimes the only) way to access key services for work, education, government, social services, health, and more. In many ways it’s becoming as important to daily life as electricity.

Personally, I wish broadband internet service (both “wired”, like cable modems, and wireless, via smartphones) was regulated as a utility — because then providers would have a far greater responsibility to make sure customers have truly reliable service. They also would be more accountable for performance.

Under the current scheme, it’s too easy for non-tech-savvy customers to end up stranded without resources by their ISPs who can afford to neglect them.

This situation was stressful enough for me — and I’m tech-savvy enough to figure out at least part of the problem, and I also had an expert I could call for help. To someone who lacks these resources, this situation would look pretty hopeless.

This whole fiasco made me wonder: How many people end up giving up on home broadband, and the opportunities it affords, simply because their ISPs leave them stranded? Bridging the digital divide isn’t just about having computers — it’s also about having access to the internet that works and that keeps working.

Right now, ISPs should be willing to provide at least some basic education about connectivity needs beyond the products and services they sell — enough to help non-technical customers get started solving their own connectivity problems. The current situation (“Not our fault, sorry. Good luck. Bye!”) is callous and untenable.


…I’m sure I’ve overlooked some issues, and that there must be some existing resources that would be useful to the typical consumer out there. I’d appreciate comments below that fill in some of those gaps, and I’ll update this post (or create new posts) to expand upon that information.

Note that I cannot solve other people’s connection problems, so I won’t publish comments seeking personal assistance for individual difficulties. I’d like to try to build a bit of a consumer-friendly resource here.

8 thoughts on What to do when your home wifi stops working and your broadband provider can’t fix it

  1. Pingback: What to do when your home wifi stops working and your broadband … | Wireless Fans

  2. thanks, but it’s no help to me, nor too most of us. you seem to expect that everyone has apple products but, in reality, most do not. any help for us MAC non-users?

  3. Actually, the most important parts of this advice DOES apply to anyone, regardless of what kind of equipment you have.

    You should be able to designate a specific DNS on any system. Likewise, you should be able to find other high-end routers (besides the apple airport extreme) and wifi analysis software to work with any kind of computer. You’ll have to do your own research to find the best devices and software for your setup.

    I shared my details for my Apple system because it will be useful for many people. But the core strategy and advice here applies to anyone — even those unfortunate enough to be using Windows PCs.

  4. I found your writing on this subject very interesting and informative. I couldn’t believe that your issue, at least in part, was just a fault DNS. It’s a lesson I actually learned last year when my Verizon DSL started having similar problems that tech support couldn’t help me with.

    A suggestion that you didn’t mention, or that I couldn’t find in your article, would be to update a modem’s firmware and/or change the mode of WiFi signal your modem broadcasts such as 802.11n, 802.11g, etc. Some devices don’t interact with specific Wifi modes as well as others. This has helped improve Wifi performance on my iPhone 4. Another suggestion which, at least to my knowledge, works only for Windows users is to flush the DNS resolver cache from time to time to make sure that DSN records are kept up to date. I’d explain it here but a quick google search will provide plenty of relevant hits.

  5. I agree with Amy, I recently switched to Mac so I can confirm that changing specific DNS addresses is relevant to both Windows and Mac users alike. The same goes for routers and Wifi software.

  6. Excellent writeup. DNS is an extremely common failure point in all networks. DNS is so simple that it can confuse even well qualified IT gurus. This is why I take a particular interest in the topic.

    For Windows users, there is usually a WiFi analyzer within the 3rd-party WiFi utility (like Dell’s Wireless Utility), but also the built-in Windows WiFi settings have a site analysis that will show channels and signal strength within your range.

    Whenever I setup a wireless router for anyone (which I do often) I always change the default channel — which is usually 6 — and put OpenDNS servers in the router so that anything that connects to this particular WiFi connection will be using OpenDNS. Doing this, I am hoping to avoid a call in the near future claiming that the WiFi I just setup is no longer working.

  7. Thanks for the informative post! I recently moved to New Orleans and dealt with setting up my wireless network in my new house. I had to call out cable and broadband provider, Cox Communications, a few times before I had a stable connection to the modem (after trying to replace the modem as one fix, to no avail). After running my wifi for a month or so, the instability returned. I also ran up against the cable/broadband company charging for a visit from their technician since they figured that the problem had been solved in the prior visits. What I learned:

    1) It doesn’t hurt to go ahead and pay the small monthly “insurance” fee that guards against having to pay for a visit from the cable/broadband company’s technicians. I am the last person to ever want to pay this fee, but until it is established that the internet service is stable, especially in a new installation, it is better than paying the $75 and up per-visit cost, at least for the short term.

    2) Check the cable splitters. As a matter of fact, go ahead and replace them if they aren’t in an almost new condition. Many times it is the cable company’s responsibility to provide working splitters to the router, however even a faulty splitter can pass most operating tests given by the technician or when done remotely by the cable company. After numerous calls with no solutions from the cable company, I replaced the splitter and voila, problem fixed.

    3) The cable company will almost always blame the wireless router for wifi stability issues. Have the wifi router tested (on a friend’s system, perhaps) and diagnosed before calling with the cable/broadband company and let them know that it is running A-OK when you call for tech help. This can be easier said than done, but it helps.

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