What Is a ‘Whitelisting’ Policy for Zero-Fee Transactions?

A 'whitelisting' policy for zero-fee transactions is a custom rule set by a miner or mining pool to allow certain zero-fee transactions to be included in their blocks. This policy is typically reserved for their own internal transactions, such as payroll or fund consolidation, to ensure they are confirmed without a fee.

It is a deviation from the standard profit-maximizing algorithm, which would otherwise reject all zero-fee transactions. This policy ensures operational efficiency for the mining entity.