On Sun, Feb 08, 2004 at 02:31:36AM +0200, Ilya Konstantinov wrote: > On Sat, Feb 07, 2004 at 09:47:31PM +0200, Micha Feigin wrote: > > Its actually quite easy to do. I reset mine once when trying to fix a > > faulty card. If some sits at a point that they can sniff you network > > traffic they can get the mac address from the arp requests and then > > change the address on their card. > > You're talking about changing the Ethernet card's MAC address, which > can be easily done with "ifconfig ethX hwaddr ...", while we're talking > about the cable modem's MAC address. >
Sorry I wasn't awake enough wasn't thinking right. That would make it harder. > The cable modem's MAC address is unique and unchangeable (as the > standard dictates), and it's your only form of authentication (proving Supposedly its that way, only AFAIK hardware suppliers reuse mac addresses. > the right to receive service) and identification to the cable company. > > Just as they know your eligible for service at all, they can also mark > certain MAC addresses as eligible to receive real IP addresses of some > ISP. > > -- > > Changing the modem's MAC address is supposed to be hard: The customer > should be unable to upgrade firmware from his side. Only the cable > company can do it (dictated by the standard). > So, you're left with the following options: > 1. Find a security hole in the modem. Find a way to upgrade firmware > through it. Can be done with a few google searches for most modems. Depending on the modem software used in the modem can occasionally be done using telnet if you really know what you are doing. > 2. Soldier out the Flash chip and reprogram it. > 3. Build your own cable modem: build the hardware (a tuner, a > modem...), write the software... > Are there pci cable/adsl cards (I think there are at least adsl), would probably be easier with those. > That's why its considered beyond the reach of the casual service thief > or network intruder. > Yes, that would make it harder, but with a bit of investment getting a breakable modem (some googling and then some shopping) can still be done relatively easily. Will take more investment then what I suggested. And yes, it would make life harder for the ISP to allow dhcp access. Another solution for the OP would be to invest in a modem that can do PPTP itself (do they exist? I know PPPoE/PPPoA/Bridge do) and then the modem would keep the connection up and all the OP would have to do is to connect to the modem and not start the tunnel to the ISP. > -- > > Oh, and sorry if that "cable networks 101" wasn't needed. Hope someone > finds it useful :) > ================================================================= To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
