Comcast For The Win - Power Cycling Your Cable Modem Is Useless

For those of you with a cable service provider, the first item on the tech’s script involves “power cycling” your cable modem. Even if you’ve power cycled your modem three times prior to calling, the technician will ask you to shutdown your computer (which serves no purpose), power off everything relavent to the network, wait two or three minutes, and finally turn everything back on. Most user’s won’t mind, but for some people, having to restart your entire network can cost you some money, especially if you have people/other networks that depend on your uptime.

I’ve worked in technical support, and I’d say about (this is a made up statistic) 80% of problems are resolved by simply rebooting the computer. Despite restarting the machine prior to calling my ISP, the tech at the other end of the line either doesn’t believe me, or thinks because he/she is telling me to do so, the connection will automatically restore itself. I comply most of the time just to humor them, but I know the problem will continue to exist.

So I’ve logged back in and still have no connectivity - this is usually when I start taking control of the call. This is how things (usually) go…

Tech: Mr. Patterson, would you mind clicking on start, then run, and typing…

Patterson: Yes, my IP address reads 0.0.0.0 - DHCP is still not assigning an IP address.

Tech: Ok Mr. Patterson, is there a splitter between the wall and your cable modem?

Patterson: No, the cable modem is plugged in directly to the wall.

Tech: Ok, do you use a router or have multiple computers networked together?

Patterson: yyeess….

Tech: Ok, would you mind connecting your cable modem directly to your primary computer? Just eliminate the router or hub.

Patterson: Yes, I would mind. What makes you think my computer will pull an IP address if my router wont?

Tech: Well sir, the router could be defective, misconfigured, or not connected properly.

Patterson: So you’re telling me three different routers are bad? I’ve tried THREE separate routers, I doubt they’re all defective.

Tech: You could have a bad network card too.

Patterson: If that were the case, I wouldn’t be able to login to my router and see your DHCP server is failing to assign me an IP address!

Tech: please hold…

Tech: Mr. Patterson, I’m not getting a response from your cable modem, it’s probably bad.

Patterson: Highly unlikely… There haven’t been any storms, power surges, physical impacts, or water near this modem.

Tech: Well sir, we’re going to send a technician out there and have him replace your cable modem with a [isp company name] modem.

Patterson: First of all [isp company name] doesn’t manufacture cable modem’s so it’s probably some cheap RCA brand. I have a spare cable modem that I know works, give me just a sec.

Tech: Ok, no problem.

Patterson: Alright, still no IP address. Are you sure there aren’t any outages or wrecks?

Tech: please hold…

Tech: Sir? Ok, we’ve actually had eight other users within three blocks from your house call in to report connectivity issues. I did some investigating and there are Line Tech’s working in the area. Your connection should come back on-line within the next hour or so.

Patterson: And you didn’t tell me this in the beginning…… why?

Tech: I’m not sure sir, is there anything else I can help you with today?

Patterson: Get Bent…*click*

So what happened here? Let’s start from the beginning. An IP (internet protocol) address is what identifies your computer or network on the internet. IP addresses start at 1.1.1.1 and have a maximum value of 255.255.255.255. Think of an IP address as a street address, but for your computer or home network. Everyone’s IP is unique, and usually assigned via DHCP. DHCP is a protocol that automatically assigns an IP by sending out broadcasts. The keyword here is “automatically.” There’s absolutely no need to restart a device (router, computer, etc) if your ISP use’s DHCP (this is also assuming the computer is not infected with adware/spyware/virii). Most routers have the ability to “release” (clear the assigned DHCP address) and “renew” (grab a new IP via DHCP). 9 times out of 10, if your router or computer is unable to “Repair” or “renew” the IP, it’s a problem with the ISP. That 10th time is probably a hardware problem on your end, which you should determine prior to calling up and haggling with these lame, under-trained, under-paid techs.

“J-Ruck, how do I know if my hardware is defective?” Great question. Let’s say you have three computers in your home, but only two of the three can get to the outside(WAN or wide area network). Common sense tells us the root of the problem lies within the single computer having difficulty, not the router or WAN device (device connected to the internet). How can we be sure? Before we go any further, observe the following illustration. This image represents our network (not wireless).

For the purpose of this article, we’ll say “Comp A” is having difficulty accessing the internet. The first thing I would do is log into the router (http://192.168.1.1/ or ssh -l admin 192.168.1.1) and make sure the Comp A IP address is listed in the DHCP clients table. If Comp A isn’t listed, either the port on the router is bad, the network port on the computer itself is bad, the cable connecting the two is bad, or there’s something wrong with the network configuration within the operating system (Windows XP, Windows 98, Linux, etc). Usually the problem is a little more sever, and not as easy to troubleshoot. If two of the three computers can get on line, the cause of the problem is not the ISP.

The most common issue we face involves the entire network going down. There’s a couple ways to determine where the problem is occurring. Looking at the diagram above, we can safely eliminate that big cloud labeled “internet.” Unless Bush decides to star in another episode of, “The Decider”, I doubt the internet is going anywhere. So log back into your router and find the option similar to “Status” or “DHCP” or “Info” - use your head; we’re looking for the WAN IP. The next time you call your ISP and they ask for your IP address, don’t even bother unplugging your PC from the router, then plugging it into the cable modem. Just make sure you don’t follow their (start, run, cmd, ipconfig) directions and give them the LAN (local area network) IP. Depending on the manufacturer, LAN IP’s typically begin with 192.168 or 10.10. Your WAN IP will typically remain within a certain range. For example, my ISP is Comcast and my IP usually begins with a 68 or 69.

If the WAN IP field is filled with 169.x.x.x or 0.0.0.0, then you’re not receiving an IP from your provider, therefore the problem is with them, or your cable modem. I have multiple pieces of hardware so I’m able to determine where the problem exists. Having a duplicate of something usually helps in the computing world - troubleshooting becomes much easier.

There are hundreds of possible combinations as to why your connection isn’t connecting. The point is this… Computers do what user’s(you) tell them to, it’s just that simple. There’s nothing overly complicated or out of this world about computers - just take the time to do a little research. Google is your best friend, and I mean that. There’s a directory at work that contains the other offices around the state. The directory is so unorganized, it’s just easier to goto Google and type: [city] [state] [company]. If something isn’t clear, highlight it with your mouse, copy the highlighted portion, paste it in Google and click search!

ps. Don’t use wireless - I’ve seen 64 character WEP keys cracked in less than 10 minutes *b0oM* you’re entire network is infected.