All cable modems will cache the CPE (customer premise equipment) MAC address but will be configured (on boot) by the cable company to only permit a particular number of unique MAC addresses to access out. The MAC is stored in volatile memory, so usually powering the modem down for a few minutes will discharge the caps and wipe the cache. I suppose it's not out of the question that your cable company does MAC level filtering on the IP level, but most I've seen are way too lazy.

That's just disgraceful. I 'm pretty sure this doesn't happen in Greece. I 've never heard someone having to wait for his device's MAC to be approved.

 

Thats the way it used to be. On our modems now it takes 3-6 hours to refresh a new MAC before it goes live. Unplugging and resetting do nothing. Now that doesn't need to be done if your running thru a router. It will connect it instantly.

 

Oh, that's only for a modem, not a router. Makes more sense, but still...