user35717: I understand replace-by-fee transactions are no threat to merchants who require multiple confirmations. However many businesses still accept 0 confirmation transactions as a means of improving usability and help with marketing. I expect demand for 0 confirmation transactions to continue (at least for transactions with a value below a certain economic threshold). What is the easiest way to automatically reject all RBF transactions?

user24974: Replace-by-fee (RBF) transactions all have a sequence number that is below MAX - 1.  If the payment a merchant receives comes from a transaction that has such a sequence number, the merchant can either wait for the transaction to be included in a block, or ignore the payment altogether.  Ignoring the payment is fraught with other complications, however, since the bitcoin will still go to the merchant if included in a block.  The customer would have to replace the transaction, using RBF, before it is mined.  It's probably easier for most merchants to simply wait for the first confirmation.

35717: <p>I understand replace-by-fee transactions are no threat to merchants who require multiple confirmations. However many businesses still accept 0 confirmation transactions as a means of improving usability and help with marketing. I expect demand for 0 confirmation transactions to continue (at least for transactions with a value below a certain economic threshold). What is the easiest way to automatically reject all RBF transactions?</p>
 24974: <p><a href="https://bitcoincore.org/en/faq/optin_rbf/">Replace-by-fee (RBF) transactions</a> all have a sequence number that is below <code>MAX - 1</code>.  If the payment a merchant receives comes from a transaction that has such a sequence number, the merchant can either wait for the transaction to be included in a block, or ignore the payment altogether.  Ignoring the payment is fraught with other complications, however, since the bitcoin will still go to the merchant if included in a block.  The customer would have to replace the transaction, using RBF, before it is mined.  It's probably easier for most merchants to simply wait for the first confirmation.</p>
