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gawdknows

Technical User
Mar 4, 2003
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I read this from a PC mAGAZINE:-
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A DSL connection is point-to-point, not broadcast, so your bandwidth is precisely that: yours - in terms of how much data you can send and receive, and in terms of who sees it. Because cable modems utilize what is essentially a broadcast technology, packets destined for your cable modem (and ultimately your computer) are also sent to every nearby subscriber's home or office. Their computers are of course configured to examine these packets, determine that they are not intended for their node on the network, and discard them. It is a simple matter, however, to change this configuration to "capture the traffic" of fellow cable modem customers.

"The problem with cable modems is that they are really network connections. Any two-way cable modem system opens the network users to complete vulnerability. I've already chatted with a friend who put a network snooping tool on his cable modem-based Internet connection; he said it was interesting to see what the preacher down the street was downloading in the wee hours." -- John C. Dvorak of PC Magazine
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My Questions:- can anyone tell me of such a "network snooping tool" .

Secondly : the author says "Their computers are of course configured to examine these packets, determine that they are not intended for their node on the network, and discard them."how is this done, I have a cable modem too. How does my node know about the unintented packets ?

AND Finally : The author says "It is a simple matter, however, to change this configuration to "capture the traffic" of fellow cable modem customers."

what is this 'simple matter' by which one can "capture the traffic" ?

TIA
 
I can think of no Business reason why a Computer Professional would ask this question. Can you?

I tried to remain child-like, all I acheived was childish.
 
I can't think of a business reason, but it is an intellectually interesting problem if you don't understand networking.

The network snooping tool that you are looking for would be ethereal or tcpdump or snoop. Ethereal and tcpdump have been ported from Linux to Windows, and snoop runs on Solaris and has ports to other *nix platforms. These are probably not installed, and will not simply run on your cable modem, but they will give you the conceptual understanding of packet sniffing.

By default, your NIC card will discard any packets that are not destined for it based on the Layer 2 MAC address. These packages use the libpcap that was developed at Berkeley to perform packet capturing by putting the NIC into promiscuous mode. Promiscuous mode is a test mode that tells the NIC to ignore the Layer 2 filtering, and collect all packets on the network that it sees.


pansophic
 
All

Thx. for the feedback, Firstly.

Yes you are on the dot, I do not have any Business/commercial reason to ask this query, but if my neighbour down the street is continually 'watching' me ,that is something that will make me feel very uncomfortable indeed.So my point of view was more 'privacy' reasons , and in fact only 'privacy' reason.

Quoting "These are probably not installed, and will not simply run on your cable modem", so do I understand that these sniffing tools do NOT get installed on a run-of-the-mill cable modem.

Finally, my understanding is and correct me if I'm wrong, 'capturing traffic' is only done when NIC is in Promiscuous mode . so that would mean, these sniffer tools render the NIC to a Promiscuous mode. so to conclude [ and my biggest concern] if this snoopy neighbour has installed such a program on his cable modem, then it renders his NIC to Promiscuous mode and then he can happily view all that I am browsing or surfing. Right.

"So how do I get to know that I am being watched ?" !!!

Frankly this the nucleus of my problem. The article I referred to opened me up to the fact that cable modems are vulnerable when compared to ADSL lines [I being the user is exposed]. Is there any way for me to see that I'm being 'watched' ? I mean I don't want to snoop on anyone, I just want to know who is snooping on me.
I have win32 machines at my home,MOTOROLA cable modem[Surfboard], and a wireless router.


**PS:-
and One final advice :-

so do I dump my cable modem company and switch over to a ADSL company ? because I hate being 'watched' [ just as any other person]
 
I still fail to see why training more people to spy on networks helps your condition?

I tried to remain child-like, all I acheived was childish.
 
As you wish Sir and a very nice day to you.
Thank you.
 
Being on a cable modem simply increases the ease with which you can be targeted directly. Indirect targeting of data occurs quite frequently, and since most traffic is passed in the clear, all of your content can be collected, viewed and stored.

Your ISP has a full view of what you are doing, regardless of whether you have cable or DSL. If you would like a more private connection, I would suggest that you use an anonymizer service, which will set up an SSL encrypted tunnel to one of their servers, and pass all of your web traffic through it. They do a similar service for email as well.

But the understanding that you really must come to is that NOTHING that you do on the Internet is truly private. Even in the encrypted transports, such as SSL, TLS and ssh, the data at both ends is in clear text. You must plan on the fact that someone other than the intended recipient may see it.


pansophic
 
if the question is how NOT to get your data stolen, then we have lots of advice, it was only the question "How DO you steal data" I won't answer.

1. use a router even if you only have one computer, it is much harder to hack a router than a PC.

2. Install a personal Firewall on your PC, the ones I use tell you what on your PC is trying to talk out to the net

3. Encrypt data at least ZIP it, even better PGP

4. VPN data to a business

5. do not allow file sharing through the router


I tried to remain child-like, all I acheived was childish.
 
Thank you
yes, protecting my 'data'[privacy] was of the real concern.

and wishing all a Merry X-mas !!
 
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