Office network going down, need help BIG TIME

[The Mailman]

Okay so having spent the last day and a half trying every possible setting and config I could think of I figured I'd ask you guys, since you always know, and all

I've been setting up an office network, all PCs connected to a D-Link switch, then to a Belkin router, then to a cable modem

I'm in the process of switching over from a DSL ISP to cable.

This setup (pc>switch>router>modem) works fine on the DSL line. No IP problems (duh), nothing.

Now on the dynamic cable line, I keep having this problem.

...I set up all computers as above. I go through the office, EVERY computer is working, downloading, all is fine. All PCs are set to auto, the router has DHCP enabled.

...then out of nowhere, sometimes a few minutes, recently it took 15 minutes, EVERYTHING goes offline. Router says it cannot find the modem / connection is offline. The modem says its online, but not sending/receiving. Cycle through and things go online again. Rinse, repeat.

Why is everything going offline like this? This is the 2nd router I've tried so far, so I think I can safely say it's working fine, especially since its fine on the DSL. Same goes for the switch. The ISP tells me the modem is working fine and that it's something on my end.

Ideas?

 

[Fardringle]

When the office loses Internet connectivity, are the computers still able to communicate with the router and with each other? If so, then you either have a problem with the WAN port on the router or an issue with the modem or the ISP connection. Since you said that you tried a different router,that points to the cable between the modem and the router (I assume you tried a different cable?) or an issue with the ISP.

While it would put everyone else out of work temporarily, there is a fairly easy way to verify this. Connect a computer that you know is good directly to the cable modem without a switch or router (make sure the software firewall on the computer is enabled). If it still loses connectivity then you know that it is a problem with the ISP and you can give them evidence that this is the case.

 

[Crusty]

Call the ISP back and tell them to actually come out to your office and run tests. All to often I've been told 'it looks fine on our end' when in reality it is there end with the problem.

To really rule out the router as your problem, make sure you enable your software firewall and then hook a computer up directly to the modem. Run a continuous ping in the background to some IP, I usually pick one 2-3 hops into my ISPs network, and then just wait and see what happens while you use that computer as normal.

 

[The Mailman]

When the office loses Internet connectivity, are the computers still able to communicate with the router and with each other? If so, then you either have a problem with the WAN port on the router or an issue with the modem or the ISP connection. Since you said that you tried a different router,that points to the cable between the modem and the router (I assume you tried a different cable?) or an issue with the ISP.

While it would put everyone else out of work temporarily, there is a fairly easy way to verify this. Connect a computer that you know is good directly to the cable modem without a switch or router (make sure the software firewall on the computer is enabled). If it still loses connectivity then you know that it is a problem with the ISP and you can give them evidence that this is the case.

lol, as I was about to reply to your post, it happened again. I guess it's a good thing, since I can check everything again to make sure this description of the error is correct.

I can connect to all computers online on my network/homegroup. Intra-office connection and printing (also on the network) is fine and unaffected.

Router CP tells me the internet status is "no connection"

Previously I was thinking this might be an IP conflict thing, but since I am the only person here at the moment...I think I was the only PC online when this happened as well. One was shutting down while this happened. Either way, this shouldnt be an IP thing considering all of the above, right?

Modem is online, not sending or recieving. About to call ISP now.....POOF, internet is back online. Didn't power cycle or change anything this time to fix it.

What to do?

(edit: just replaced both cables (modem to router, router to switch) for the heck of it to rule that out)

 

[RebateMonger]

While it would put everyone else out of work temporarily, there is a fairly easy way to verify this. Connect a computer that you know is good directly to the cable modem without a switch or router (make sure the software firewall on the computer is enabled). If it still loses connectivity then you know that it is a problem with the ISP and you can give them evidence that this is the case.

This is what I'd do.

For "evidence", use the following command at an administrator-enabled Command Prompt:

"ping -t yahoo.com>c: \ping.txt" (no space between c: and \ping.txt )

That'll continuously ping Yahoo.com and make a text file of the results. Hit Control-C to end the log. You can open the log file if needed to view the results up to the time you open it. No need to stop the pings to take a quick look at the log file.

 

[Fardringle]

Modem is online, not sending or recieving.

Does this mean that the Send and Receive lights on the modem are actually off, or just that you can't send/receive through the modem? If the lights are off, then it is definitely a modem/ISP problem.

 

[The Mailman]

Does this mean that the Send and Receive lights on the modem are actually off, or just that you can't send/receive through the modem? If the lights are off, then it is definitely a modem/ISP problem.

the lights are off (other lights, like Cable stay on)

i said this to the tech on the phone, he told me "as long as the cable light is on, then the signal is good. If the send/receive arent on, thats just indicative of your computer not sending anything from it / not trying to download. The problem is with your router."

 

[Fardringle]

the lights are off (other lights, like Cable stay on)

i said this to the tech on the phone, he told me "as long as the cable light is on, then the signal is good. If the send/receive arent on, thats just indicative of your computer not sending anything from it / not trying to download. The problem is with your router."

This is B.S. The tech you talked to either doesn't have a clue or was just trying to get you off of the phone (again, probably because they don't have a clue).

If you have a Motorola modem, the Send and Receive lights have three different settings. On continuously means active and connected. Flashing means it is trying to connect. Off means no signal at all. I haven't worked much with other brands, but I assume it would be similar. The Activity (or PC) light is the one that indicates when your computer(s) are using the connection.

 

[RebateMonger]

Also, you can take a look at the STATUS page of the cable modem (if your ISP has set the modem to allow it). For a Motorola modem, you can access it at http://192.168.100.1 .

 

[The Mailman]

do i have to be plugged directly into the modem to get into that?

 

[Crusty]

Nope, assuming your network isn't using that address already it's not in your route table so your router will forward it along and the modem will respond.

 

[The Mailman]

i'll give it a try tomorrow, thanks

unfortunately, they've already outsourced another tech company to come in the morning to "fix what I couldn't" so I guess once they come to the same conclusion (the ISP) and bill us for god knows how much, I'll give it a shot and ream out the ISP

 

[The Mailman]

tech here, says its the belkin routers not jiving with the modem

weird, since i use belkin at home with the same ISP and no problems

cloned MAC address....working so far, we'll see

either way the company is building a linux router/firewall for us so we'll be replacing the belkin regardless (i guess i'll keep it for wireless)

 

[The Mailman]

okay so now that the tech is gone, 10 minutes later the signal dropped again.

cloning the MAC address fixed things again, but it seems this will be temporary

do i go exchange the router for another brand? demand from my ISP a new modem? right now we have a scientific atlanta in there


btw, when this happens, when i try to access the modem (192.168.100.1) i cant get in. what is this indicative of?

 

[aE0n]

You need to tell your cable ISP to send a tech out, a long time ago. They will bring a new modem and can also check the line. Tell them you are unable to go through all their little tests and you need a tech.

 

[Crusty]

You need to tell your cable ISP to send a tech out, a long time ago. They will bring a new modem and can also check the line. Tell them you are unable to go through all their little tests and you need a tech.

If they keep on giving the OP the runaround I would be looking for a new ISP ASAP as well.

 

[somethingsketchy]

The ISP could have blocked you from accessing the modem at 192.168.100.1. Then again when I did that same IP address to my cable modem, I was able to access the info page where I can see the signal-to-noise ratio, among other things.

I remembered when I had a Motorola Surfboard, I couldn't access the .100.1 address at all. However it seems with this particular modem (some off-brand cable modem that supports phone/tv/Internet) I had no issues. So chances are you are "remotely" being denied to access that page.

 

[The Mailman]

The ISP could have blocked you from accessing the modem at 192.168.100.1. Then again when I did that same IP address to my cable modem, I was able to access the info page where I can see the signal-to-noise ratio, among other things.

I remembered when I had a Motorola Surfboard, I couldn't access the .100.1 address at all. However it seems with this particular modem (some off-brand cable modem that supports phone/tv/Internet) I had no issues. So chances are you are "remotely" being denied to access that page.

I can access 192.168.100.1 when the internet is going fine. I'm on it right now.

When the signal drops, i can't get in.

router says its online, weirdly enough, and i refresh it and it says it has an IP. Does this mean the router is blocking me from accessing the modem / it can't connect to the modem / the tech was right? The MAC address cloning fix seems to have been the quickest fix so far to get things up again, but it seems to be a matter of time until it goes down again and i have to repeat.

the tech (non ISP, this is an outside company now) told me the same thing about the modem, and that it's not the ISPs fault - as long as the cable light is on then its not their fault, so he basically agreed with the ISP on this

this is our 2nd ISP, in Toronto, there is pretty much a monopoly, we don't have more than 2 options, and option A (Bell) was horrible, dropping all the time, 23kbps speed when we're paying for 5mbps, etc

at least the new ISP (Rogers) is giving us good speed....

 

[The Mailman]

okay went down again. recloning the MAC address doesn't fix anything. I guess it was a coincidence it worked for him, as when this is done the router resets and by coincidence it worked for him.

I just cloned the MAC twice and it didnt fix anything. Cycling the modem off is what fixed things.

 

[Crusty]

I don't understand what you mean by cloning the MAC more than once. Is the router automatically changing it back to something else?

 

[The Mailman]

I don't understand what you mean by cloning the MAC more than once. Is the router automatically changing it back to something else?

I have no idea. Tech said to do it and it will work no problem....he clearly was wrong.

Called ISP, told them about not accessing modem, he agreed the modem is faulty and we'll have a ISP tech here in the next 2 hours.

*crosses fingers*

 

[Crusty]

The whole point of cloning your MAC address is that if your ISP binds your connection to a specific devices MAC then you can set your router to have that devices MAC so your modem will give it access. It typically happens when the installer installs the connection to a PC instead of a router initially and the ISP binds to the Desktop PC. So you just clone the MAC of the desktop to the router and you're on your way.

I've never ever needed to clone the MAC of the modem to the router if that's what you are doing and certainly not more than once unless your router isn't saving settings for some reason.

 

[stlcardinals]

I would think it's the cable modem. The next time it happens, just do a test of power cycling the cable modem. If it's some cheap brand, I would get them to replace it.

 

[The Mailman]

why would cloning 1 computers MAC have anything to do with fixing an entire network of 7-8 computers all on the same line?

either way, didn't work....

I would think it's the cable modem. The next time it happens, just do a test of power cycling the cable modem. If it's some cheap brand, I would get them to replace it.

cycling it last time fixed it. it's a Scientific Atlanta.

I told them on the phone I want a Motorolla (I had one of those @ home for years with no issue) but they said it'd be a crapshoot.

 

[RebateMonger]

When the signal drops, i can't get in.

Sounds like the modem is failing.