ah, not sure then mate, never used them so i don't know what router/modems they use, so i don't know what options are in the user interface.
have you logged in to the user panel ? what make is it ?
you can use the suggestion above but some routers/modems need to be restarted for the new mac to take effect , in that casde it would not solve your problem, my netgear on TT takes 30 seconds to swap mac and i do that for the same reason , my router/modem take forever and a year to boot up.
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