If the modem is powered off no traffic will be passing through it. Of that, you can be certain.

Assuming authentication is done with user credentials you set on the modem and not just the physical cable connection (99% of providers work this way) , those symptoms describe either someone using your account, spoofing your account identification from another point on the network, or a mistake at the cable company.

I'd suggest your best course of action is to contact your provider and explain the situation. Hopefully they can give you fresh account credentials as it's the easiest possible solution and one of the most likely to resolve the issue. Beyond that, they can test your line to see if there's a foreign device, and worst case changing service providers will almost certainly resolve the issue.

I hope that helps.

I got a call from my cable company once threatening to shut me down. They claimed my computer was sending out a virus and I was instructed to immediately go to the Microsoft website and download some  patch .exe file right away or my connection would be turned off.

I replied "How am I supposed to do that? I have a Mac" and the cable guy went silent. He realized the problem lay further than his nose and told me to forget about it and hung up.

Long story short: Somebody was spoofing my IP.

No wireless connection here, just a physical cable modem.  No authentication is required (I don't even need an ISP), just turn it on and it's connected (no, there is no password in some script out of my view, it simply does not require an ISP),

I use a firewall and a resident anti-virus.  Occasionally I check the computer for spyware, but the only thing I ever found were those common cookies.  I am very careful about opening email attachments, and never do from strangers.  However, I can't check this possibility right now, as my PC resumed its constant reboot problems reported a while ago and is not even booting now - I'm going to take it for repair tomorrow.

I don't use P2P programs, except Kazaa very rarely (last time was at least 2 months ago).

I contacted the cable company yesterday and again today, but the "we will contact you in 24h tops" means in fact 2 days.  I'm going to write to their ombudsman, it seems to be the only thing that works when we have a problem there. 

I haven't used the cable yesterday and today, and transfers reached 6GB today only - this is much more than I have in total during a month!

Regards,
Adelaide 

IP emulation is very simple to do and basically it sounds to me like you've been hijacked.

But would IP emulation count towards my cable usage? To know my usage, I have to provide the modem number, not an IP address. Is it possible to "read" the modem number through a trojan/spyware/whatever that might have been installed in my PC?

Regards,
Adelaide

Quote from: Contakt on May 13, 2008, 03:52

IP emulation is very simple to do and basically it sounds to me like you've been hijacked.

But would IP emulation count towards my cable usage? To know my usage, I have to provide the modem number, not an IP address. Is it possible to "read" the modem number through a trojan/spyware/whatever that might have been installed in my PC?

Regards,
Adelaide

It would yes. It's very easy to hack into your router (or modem) and that would also include access to your system depending on what type of firewall you have or what ports are open. I don't want to go into the technical details for obvious reasons but your modem ID is the least of your problems right now. Typically what happens is your router and IP becomes a mail server for spammers and that would explain your usage going off the scale.

Quote from: Contakt on May 13, 2008, 14:05

Typically what happens is your router and IP becomes a mail server for spammers and that would explain your usage going off the scale.

But wouldn't that work only when my modem is on?

RMR, I don't need to log in.  I need the modem ID only to check the usage.  To use my cable connection, I only need to turn the modem on.  I know this is not usual, but it's how it works.  ASDL users however require an ISP, and this made cable cheaper that ASDL to us.

Regards,
Adelaide

If you've got broadband on the go using a wireless solution or something similar then you can be hacked. If it's a plugin connection ie; you're dialling up via your TV or cable connection it can also be hacked and it won't make any difference if your modem happens to be buried 20ft under the ground in a lead-lined coffin with everything disconnected. Some bad people have got access to your login details and that's all they need.

Sorry I don't have better news for you Madelaide but I understand how these issues can be extremely frustrating for the unwary.

Your solution is to get a techie who knows what they're at. I'd be able to look at your system from here but what you need is a little bit more complex than that.

Tech support of my cable provider hasn't yet found a solution, and the hacker has already dld over 100GB this month.  The provider doesn't seem however bothered about this, as long as I upgraded my account (what I will undo as soon as the "discount for you trouble" ends in two months).  They had said they would limit my speed because I had already used my 20GB quota, but they seem ok that the new quota (40GB) has been already surpassed. 

They said that nobody could have hacked it unless he had had physical access to my cable installation.  They said it's not possible to hack it from the cable in the telephone box coming all the way to the 7th floor where I live.

It doesn't seem they have any intention of fixing it.  Wouldn't changing the modem fix it on my side?  At least the hacker's counting would stop being credited to me, and I believe there must eb a way (or not?) that they can simply block that modem number from theri system.

Oh well.  I'll be a way for a week tomorrow, let's see what happens until then.

Regards,
Adelaide

I have the impression they just don't care the extra GBs.  They only used it as an excuse to make me upgrade. I said I wanted to revert it, they gave me a 2-month discount instead, and I can revert after that. And they said they won't restrict my speed because of the excess data transfer.

I know of people who use bandwidth extensively for uploanding and downloading CDs and DVDs, and they were never punished for the extra GBs (which they probably easily surpass every month with that type of use).  Maybe they pick users randomly to see their transfer data.

Regards,
Adelaide