mac address/cable modem prob

CALV

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May 17, 2001
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Hi all,
Got me cable modem on Thursday (im in UK by the way), all working fine, setup on my main pc, however I would like to setup a linux firewall, I spent until 3am Friday morning trying to get an ip assigned from my cable provider, set up the linux box to use dhcp, and EVERYTIME the dam thing recieved an IP, but it was always a LOCAL (192.168, or 10.40) IP, I phoned NTL (provider) and they said that once registered, a MAC address was assigned to my NIC, and I can have 5 of these if I want, now does that mean that if I take the NIC out of my main pc, and put it in the linux box it will work as the card will then be recognised? and then I can signup again on my windows system? All I had to do to get connected on windows was type in an ip address they gave me in the address bar and it took me to a sort of signup page, I cant do that through linux (console only- and Im not an expert- someone was helping me setup the linux), has anyone any suggestions/ideas?
Thanks


Next time you wave - use all your fingers
 

ejsmith2

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Feb 9, 2001
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I'm in the US, but I bet it works the same way there too.

The mac address is the 'address' of the cable modem itself. You give them a serial number too when you sign up, but that's just for their little 'records'. They don't have actual access to the serial number over the cable lines, but if two subscribers are found to be using the same serial number, they'll disable the accounts. Isn't it nice of them to monitor you so closely? :smile:

Anyway, the IP is for the MAC address of the cable modem. You can take your NIC card to a friends house, and it will work just fine with his modem too. It's not the card that has an address, it's the actual cable modem. Now, I use an external cable modem, so I'm completely wrong if you have an interal modem with built in NIC.

If you go out an buy a cable modem yourself, and hook it up to the cable lines, it will work just fine. For about 20 seconds. They routinely send out pings to all modems, and if a MAC address comes back that isn't on a suscriber list, they 'disable' the cable modem. If you hooked up the modem before they got all the stuff written down, you might still have it locked out of the system. Give them a call. IF the send/receive/data light is on steady right now, the cable modem is fully functional and it's a problem with your box..........somewhere.
 

CALV

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Hi,
Thanks for the reply, I finally got it sorted yesterday with a lot of help from various people. Things work similar here to the way you explained things, except the cablemodem I have is actually built into the digital tv box (i.e. the tv reciever has an rj45 socket on the back), the MAC address in my case was actually the hardware ID of the card, go to start/run put winipcfg , the adapter address shown is the hardware id of the NIC, I put the "registered" nic in the linux box and with a lot of messing finally got it online, I since found out (took 3 calls to tech support as they were clueless) I cant actaully register up to 5 cards, but aparantly only 2 can be online at once, as you said, they must scan and kill connections if too many are active.
Thanks again for the reply.


Next time you wave - use all your fingers