Look for this code in main.cpp
Code:
// Note: if you modify this code to accept non-standard transactions, then
// you should add code here to check that the transaction does a
// reasonable number of ECDSA signature verifications.
int64 nFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
// Don't accept it if it can't get into a block
if (nFees < tx.GetMinFee(1000, true, GMF_RELAY))
return error("CTxMemPool::accept() : not enough fees");
and change to this:
Code:
// Note: if you modify this code to accept non-standard transactions, then
// you should add code here to check that the transaction does a
// reasonable number of ECDSA signature verifications.
int64 nFees = tx.GetValueIn(mapInputs)-tx.GetValueOut();
if (nFees == 0)
return false;
unsigned int nSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
// Don't accept it if it can't get into a block
if (nFees < tx.GetMinFee(1000, true, GMF_RELAY))
return error("CTxMemPool::accept() : not enough fees");
