After the recent hardfork we have a winning chain and a much shorter losing chain left. However, if you are pro or agains the fork, you could still mine and use one chain or the other.
Now, there is an issue. Let's assume I'm on the non-fork chain and create a transaction, sign it and broadcast it to the non-fork network. Vitalik warned users to be aware of replay attacks:
If any users continue to be interested in following the non-fork chain, they should still update, but run with the
--oppose-dao-forkflag enabled, though they should beware of transaction replay attacks and take appropriate steps to guard against them; users with no interest in the non-fork chain do not need to worry about transaction replay attack concerns.
Now I understand the transaction would be valid on both chains. How do I prevent the transaction from being broadcasted on the pro-fork network. And how do I prevent the transaction to be valid on the pro-fork chain?