I am not a computer genius but i know some stuff so here is the problem. I do not know if someone is stealing my internet, even if it is possible but i prefer to know the facts.
Here are the details: I use Verizon DSL high speed internet. This is NOT wireless internet so don't tell me about securing router and access points (yes!! i read). Here is the setup if its necessary. There is a box outside the house with a hard line entering the house. A telephone wire is connected from the hard line jack to a high speed modem which is connected to the computer.

Someone told me this but i am not sure of its validity, so if anyone knows please explain what ARP is about. I was told to run a command named "arp -a" several times and count the number of entries i see. Sometimes i get 7 entries and sometimes i get 8 entries. Does the extra entry indicate someone else is using the internet?

So here are the questions:
1. Is the DSL type (mentioned above) stealable?
2. How to know if someone is stealing it? (Any commands etc)
3. How to find the culprit if there is one?
4. What is ARP about? and is there any validity to the above or is it just nonsense. Please explain

Thank you people!!It's pretty UNLIKELY that someone will try and hook into your wired DSL connection.  Not impossible, but unlikely.  If they are savvy enough to do that, you can bet they're savvy enough to cover their tracks beyond your ability to detect their activity.  Concentrate on securing all endpoints (computers) with a GOOD level of firewall and malware protection.

ARP is the protocol that maps machine addresses (coded into a network card) to IP addresses.  An ARP table will only report on addresses that it has seen - it is not omniscient and a switch will get in the way of a computer's ability to see other addresses.  Given that MAC and IP addresses can be spoofed, the ARP cache is not particularly reliable anyway.

Don't overlook the fact that wherever there's a connection to the internet, there's a risk.  That should be more of a concern than someone piggy backing onto your wired connection.

To answer your questions:

1.  Yes.  It would take a high level of technical expertise.

2.  Google "intrustion detection systems".

3.  An IDS may assist.  But it is rarely worthwhile expending ENERGY identifying the cuplrit.  Concentrate on making your systems secure.

4.  See above.you got firewall on? I would like to know how easy it is to hack a firewalled pc with a good firewall.

but i got a router which has hardware firewall and a software firewall on my pc .... QUOTE from: 2x3i5x on May 29, 2009, 09:56:48 PM

I would like to know how easy it is to hack a firewalled pc with a good firewall.