Can nLockTime TX be used to flood Mempools? What would happen, if I would create a large number of large transactions with a very high nLockTime?

Would something stop me from filling not only the miners', but also regular nodes' mempools?

Would miners drop transactions with unreasonably high nLockTime and low transaction fee?

What would BitcoinCore do?
There is no size limit to the mempool from what I can find. It might be possible to flood it but rather difficult and expensive / slow. I see two approaches:

A) minimum relay fee


connect to 1000 nodes
send plenty of txs that meet the minimum relay requirements

how many?: 32 000 000, 32 000 on each node
nLocktime in the far future so they don't get into blocks
tx fee: minimum relay fee: 0.0001
amount: very low
size per tx: 250bytes

mempools are filled with 8gb of dust


It would take a while to generate that many addresses and tx and get them broadcasted. Also it would cost at least 3200BTC.

B) 0 fee txs with minimum output of 0.01 so they still get relayed

Mempool is gated by a rate limiter for free tx:

// Continuously rate-limit free transactions
// This mitigates 'penny-flooding' -- sending thousands of free transactions just to
// be annoying or make others' transactions take longer to confirm.

// Use an exponentially decaying ~10-minute window:
// -limitfreerelay unit is thousand-bytes-per-minute

// At default rate it would take over a month to fill 1GB


So this will be at least very slow. Also you need to have 320 000 BTC for 8GB. :)

There might be ways to artificially make txs larger. Alternate clients might do things differently.