nat to force broadcast

Hello

I am very new to this, so I apologize if this is a very common question, but
I am trying to change the ethernet address of all the packets that my
computer sends to ff:ff:ff:ff:ff:ff. I am using

ebtables -t nat -A OUTPUT   -j dnat --to-dst ff:ff:ff:ff:ff:ff

but doesnt seem to work. Any clues what can be missing here?

Thanks

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-h