Why can't we connect wirelessly?

March 10, 2009 10:29 AM

Why can't we connect wirelessly to the internet?

We have comcast cable internet and a netgear router and fourteen computers, 13 of which connect wirelessly and one of which uses a wired ethernet connection.

Our internet connection stopped working (possibly because the modem was fried by a lightning strike near us?). None of the lights on the modem would go on, so Comcast told us to bring it in and get a new one.

After replacing the modem, the situation is this:
1. If I am wired directly to the modem, I can connect to the internet.
I am on a Mac.
2. My roommate tried to connect directly to the modem running Linux and could not get internet.
3. The router is broadcasting wireless signal. We can all connect to it and can see each other. But, when the router is connected to the modem, there is no internet coming through the pipes.
4. I tried connecting to the router and having it search for firmware updates, and it can't see the internet at all.
5. I tried the whole reset rigamarole (of router, of modem, of everything), it did not help.

So, is our router broken? Is there something else going on?
I am not super knowledgeable about computers. I usually solve problems by googling for info and bumbling about until something works. Detailed, action-oriented explainations are appreciated.

posted by mai to computers & internet (16 comments total)

The router's WAN settings arent correct. Plug the comcast modem into the router's WAN port then log into the router. Make sure it is doing DHCP for the WAN. It should be able to pull an IP address and all the settings. If youre not sure of this you should call comcast and have them walk you through it. It may be the case that comcast has to whitelist the mac address on their end too.
posted by damn dirty ape at 10:32 AM on March 10

I already talked to comcast about whitelisting the mac adress (at least I think that's what we were talking about), and they assured me that it is okay.

I forgot to add that my roommate spent 40 not-helpful minutes on the phone with comcast last night, but I may call them again if it seems like I have something to ask them. I will try your suggestion, thanks.
posted by mai at 10:38 AM on March 10

Ok. The first step is to see if the netgear is getting an IP address from comcast or not. Im guessing its not for some reason.
posted by damn dirty ape at 10:40 AM on March 10

Oh hold on a sec, did you mean the modem's Mac address or the routers? Because I haven't talked to them about the router's mac address yet.

The router is doing DHCP. When connected to the modem, it does not get an IP address.
posted by mai at 10:46 AM on March 10

Ok, thats the problem. Not sure what the solution here is, but if comcast does block by mac then you'll need to tell them the mac address of the router. Just tell them the router isnt getting an IP. Hopefully, youll get a more competent person this time.
posted by damn dirty ape at 10:47 AM on March 10

I talked to comcast again, they claim the router's mac address does not need to be whitelisted, had me powercycle things again in a slightly different order, that did not help. Their claim is now that it is a problem with the router itself. So I will call netgear I guess.
posted by mai at 10:59 AM on March 10

Hmm, check for a bad cable. When you plug your ethernet cable into the router does a light go on the front panel? If not is there a different cable you can try?
posted by damn dirty ape at 11:04 AM on March 10

Yeah I thought so too, but I've tried different cables to no avail.

Netgear's support is really terrible. I am out of ideas short of buying a new router.
posted by mai at 11:17 AM on March 10

You should be able to do a hard reset of your router. This will bring it back to factory settings. There's a reset button or something you hold down for a few seconds. Should be in the manual or on the website.
posted by damn dirty ape at 11:18 AM on March 10

Tried this, got it to reset, tried to follow the setup wizard, but no luck because the router still can't get an IP address. I am now waiting for a reply from the netgear online support.
posted by mai at 12:18 PM on March 10

There's always the chance that whatever fried your modem may have damaged the router too. Perhaps a new router is the best way to go.
posted by damn dirty ape at 12:47 PM on March 10

This just happened to me with Comcast when I moved into this house. The cable modem they gave me is retarded. It looks on both sides for its IP address on startup. My Linksys wireless router runs a DHCP server for the home network, and for some reason, when I turned on the whole setup at the same time, the cable modem got a 192.168.x.x address from my Linksys instead of from Comcast like it's supposed to.

Solution was (and still is, every time I have to reset the modem) to power off the wireless router and modem, power on the modem until all the lights do their thing (about a minute, I guess), THEN turn on the wireless router. That gives the cable modem time to get it's correct address from Comcast's DHCP server before I connect the it to my Linksys router.
posted by ctmf at 2:16 PM on March 10

You could just unplug the connection between the router and modem while the modem was booting up, I guess. You don't really need to power cycle the wireless router. You just need the modem to not be able to see it while it's doing its startup thing.
posted by ctmf at 2:24 PM on March 10

ctmf is probably right, I've had similar problems with routers and cable modems like that. The cable modem for some reason likes to remember the MAC address of the connected equipment. I've sometimes had to do it both ways:

1- Turn everything off. Turn on cable modem, let it get all its connections right.
2- Then turn on router, see if it works.
3- If it doesn't, turn everything off, and this time start up the router first, let it finish its power up sequence, then turn on cable modem.
4- Then sometimes have to go back to step one again...

When you plug the cable in from the router to the cable modem, do the various lights flash correctly? You might be in a spot where the router's WAN port has fried, but everything else is fine...
posted by gjc at 3:22 PM on March 10

Having tried various permutations of router and modem restarting, we have concluded that the only thing left to do is try a new router. Someone is borrowing one from work to test, if that fixes it we'll buy a new one. Thanks for all the suggestions that helped us narrow down the problem.
posted by mai at 9:42 PM on March 11

Turns out it was the router's WAN port. New router made everything work. Also, the ethernet port on the only computer that was hard-wired to the router got fried too. I guess it was some lightning storm.
posted by mai at 2:17 PM on April 9