Help diagnose my network problem

Factual Questions
1

We have three computers on our home network: a Dell laptop (XP), a Mac Book (OS X), and an MPC desktop (XP). The two laptops operate wirelessly, while the desktop is hard-wired to the router.

The other day, the Mac stopped connecting to the internet. It claims to be connected to the router, but Firefox is unable to find any web pages. My wife temporarily reverted to the desktop (rarely used); today it stopped connecting. However, the Dell (which I’m currently using) seems to have no problems.

I tried hardwiring the desktop directly to the modem (cable), and the same thing with the Dell; neither yielded any results. I don’t know enough about it all to know whether that indicates anything except that the connection isn’t configured correctly.

My initial instinct is that the router is dying, but I’m confused as to why one of my computers still connects with no problem.

Any ideas?

2

[QUOTE=fachverwirrt]
My initial instinct is that the router is dying, but I’m confused as to why one of my computers still connects with no problem.

Any ideas?
[/QUOTE]

Try redoing the setup for your router, if that does not work, your router could very well be on the fritz. If your router has a firmware update you might want to try that as well.

3

I agree that the router is the likely cause of the problem. Can you get into it and confirm that it’s still set up correctly? Conceivably it has been attacked; check its firewall settings, DNS, and DHCP are all what they are supposed to be.

Can the machines ping each other? See each other? Share files and/or printers OK?

4

You may have already done this, but the first thing I would do is turn everything off. Then turn your cable modem back on. Then plug your router back in, then turn your computers back on. Your ISP may have changed your IP address and sometimes that makes things wonky.

5

Write down all the settings before you do this! Just in case.

6

[QUOTE=levdrakon]
You may have already done this, but the first thing I would do is turn everything off. Then turn your cable modem back on. Then plug your router back in, then turn your computers back on. Your ISP may have changed your IP address and sometimes that makes things wonky.
[/QUOTE]

Yeah, done that several times. Lately I’ve had to do so fairly often, which reinforces the idea that the router is dying.

Oof. And here I reveal my ignorance. I can’t figure out how to do all these things.

At the moment, the extent of the “network” is three computers connecting to the same internet. I’ve never gotten around to setting up a true network with file sharing/print sharing etc.

7

[QUOTE=fachverwirrt]
Yeah, done that several times. Lately I’ve had to do so fairly often, which reinforces the idea that the router is dying.
[/QUOTE]
You did everything in the order I said? Don’t mean to nag, but I’ve got a Mac and two PCs networked to a Linksys router and I thought it was dying but the problem was my ISP Comcast having lots of little outages and sometimes the computers could keep up but eventually they and the router got confused with constantly changing IP addresses.

You said you hooked a computer up directly to your cable modem and that didn’t work, which tells me it’s not your router, it’s your computer being confused by the IP address it’s getting from the cable modem (your ISP).

8

[QUOTE=levdrakon]
You did everything in the order I said? Don’t mean to nag, but I’ve got a Mac and two PCs networked to a Linksys router and I thought it was dying but the problem was my ISP Comcast having lots of little outages and sometimes the computers could keep up but eventually they and the router got confused with constantly changing IP addresses.

You said you hooked a computer up directly to your cable modem and that didn’t work, which tells me it’s not your router, it’s your computer being confused by the IP address it’s getting from the cable modem (your ISP).
[/QUOTE]

I was doing it in that order, but perhaps not giving the modem enough time to set before plugging in the router.

I just did everything very slowly and deliberately. Now the Mac works, the Dell doesn’t, and the desktop still doesn’t work. I don’t really care about the desktop, but I’d like the Dell to work. One more try, I guess.

9

And we’re back to the Dell working and the Mac not. This was after an intermediate step of neither working. I think I’m giving up for the night.

10

[QUOTE=fachverwirrt]
And we’re back to the Dell working and the Mac not. This was after an intermediate step of neither working. I think I’m giving up for the night.
[/QUOTE]
Doesn’t sound like your router, but switch the cables. Put the Mac in the working slot the Dell is using, and the Dell in the non-working Mac’s slot.

11

[QUOTE=levdrakon]
Doesn’t sound like your router, but switch the cables. Put the Mac in the working slot the Dell is using, and the Dell in the non-working Mac’s slot.
[/QUOTE]

There are no cables. It’s all wireless.

(Well, ok, there are cables. There’s the main data cable running into the modem, a network cable running from the modem to the router, and a network cable running to the desktop (which I’ve stopped worrying about). But no cables running to either the Dell or the Mac.)

Should I try hard-wiring things to the router?

12

[QUOTE=levdrakon]
Doesn’t sound like your router, but switch the cables. Put the Mac in the working slot the Dell is using, and the Dell in the non-working Mac’s slot.
[/QUOTE]

probably not going to matter because IP addresses are assigned out dynamically by the router as machines come online. I’d still bet you have a MAC conflict between ISP and router. Its a PITA, happens to techs too, especially when you have an ISP that may take 3…4…10min (SBCATTYahooWTFAreWeCalllingItThisWeek DSL I am talking to you) to recognize a new user logon.

It is very tempting to think you did something wrong and try again when the servers at the ISP are the problem, not the modem/router/puter.

13

I don’t know much about wireless and I hope someone who does comes along. What I wanted you to do is determine if any ports on your router are bad. That can happen. If you’ve got your Dell hooked up to port #1 for instance, and it works, try hooking your Mac to port #1 and if it works, you know that port works.

14

[QUOTE=fachverwirrt]
There are no cables. It’s all wireless.

(Well, ok, there are cables. There’s the main data cable running into the modem, a network cable running from the modem to the router, and a network cable running to the desktop (which I’ve stopped worrying about). But no cables running to either the Dell or the Mac.)

Should I try hard-wiring things to the router?
[/QUOTE]

Make sure you do it in an organized way; otherwise, you’ll get to a point where you can’t remember which combinations you tried! Trust me, I’ve been there.

First confirm constant network connection: connect Dell to the Internet (that is, outside your house) directly. Give it some time to fail. Sometimes a provider has intermittent failures that you have to account for.

Then do the same for the Mac.

Then, if (and only if) you’re sure about the Internet connection, connect the Dell by wire to your router’s port 1, and connect the router to the Internet. Test again. Repeat with the Mac. Give some time to test failure.

If this works, connect the Dell to port 1 and the Mac to port 2 and test.

If this works, connect the Dell to port 2 and the Mac to port 1 and test.

If this works, test wireless.

Report back with results. IMHO, this could be anything: ISP failures, cable/DSL problems, modem problems, router problems, even wireless reception problems.

Once upon a time I had problems that I swore were due to a bad modem. Turned out that the phone company had a problem with my DSL line. Another problem I had turned out to be a bad modem power supply. In all the years I’ve been using home broadband, I’ve never had a router or print server fail on me, and I leave them on constantly. For that matter, the same is true for modems; the only failure traceable to hardware was the power supply and the phone line.

Good luck!

15

[QUOTE=levdrakon]
I don’t know much about wireless and I hope someone who does comes along. What I wanted you to do is determine if any ports on your router are bad. That can happen. If you’ve got your Dell hooked up to port #1 for instance, and it works, try hooking your Mac to port #1 and if it works, you know that port works.
[/QUOTE]

Well, neither is really “hooked up” to anything. It’s very possible that one of the ports is bad and that’s why the desktop hasn’t been working. But the laptops are completely wireless.

Neither laptop has at any time had difficulty connecting to the router; only to the internet.

16

Make sure you are getting a DNS assigned by the router. I don’t know about the PCs, but on the Mac, you can explicitly assign a DNS, in the Network System Preference pane. I use OpenDNS: 208.67.222.222

I have seen lots of cases where the router doesn’t hand-off the DNS to client computers; this will fix it.

17

[QUOTE=fachverwirrt]
Oof. And here I reveal my ignorance. I can’t figure out how to do all these things.

At the moment, the extent of the “network” is three computers connecting to the same internet. I’ve never gotten around to setting up a true network with file sharing/print sharing etc.
[/QUOTE]
OK, forget the sharing stuff. First write down the IP address that has been assigned to each machine; on a PC you go to a dos box and do IPCONFIG (that will also show you the DNS and DHCP status if you do IPCONFIG /All); I forget the name of the Mac networking utility to get the same info but hopefully you know or can find that.

Once you have all 3 IP addresses you can try 1/ pinging the router from each workstation (it’s usually 192.168.1.1 and they will commonly be .2, .3, .4 and so on) and 2) pinging each workstation from each other one. Let us know the outcome of each of those tests, thanks.

18

[QUOTE=Askance]
OK, forget the sharing stuff. First write down the IP address that has been assigned to each machine; on a PC you go to a dos box and do IPCONFIG (that will also show you the DNS and DHCP status if you do IPCONFIG /All); I forget the name of the Mac networking utility to get the same info but hopefully you know or can find that.

Once you have all 3 IP addresses you can try 1/ pinging the router from each workstation (it’s usually 192.168.1.1 and they will commonly be .2, .3, .4 and so on) and 2) pinging each workstation from each other one. Let us know the outcome of each of those tests, thanks.
[/QUOTE]

Alright, now I’m really confused. When I got home, the Dell connected to 192.168.1.3, the Mac to 192.168.1.2, they could both ping each other and the router (at 192.168.1.1), but no internet. I reset everything, now the Mac is still at 192.168.1.2, the Dell is entirely different and can’t ping anything (the Mac can still ping the router), but now the Dell has internet.

Urk.

19

[QUOTE=fachverwirrt]
I reset everything, now the Mac is still at 192.168.1.2, the Dell is entirely different and can’t ping anything (the Mac can still ping the router), but now the Dell has internet.

Urk.
[/QUOTE]

what is the dells IP addy? If its not 192.168.x.x your router is not correctly configured. Sounds like your router is in bridge mode or something similar.

20

Something is radically wrong with that router. Either it’s been attacked, or is faulty.

Such as what? Not even in the correct subnet? Its behaving as if there is another DHCP provider on the network, if so. Did this only happen when some device was attached to the network, maybe a Windows server, another router, or something?