A simple DOS attack while IBD could be as follows:
- The fresh client is currently downloading block 100.
- Then it is offered 10 blocks at height 101, each claiming they are the heaviest chain
- 9 out of 10 alternatives are with fake PoW but still the client will waste time in getting the entire block and validating their PoW.
How does the current implementation of P2P protocol in bitcoin-core handle this sort of DoS attack?