Bitcoin Core will typically connect with not less than 10 outbound friends (8 common, 2 blocks-only). It can ask the entire friends for his or her chaintips after which begin synchronizing the header chain for the chaintip with probably the most work after selecting a single header sync peer. Solely when it has acquired all block headers of the peer and validated them to the extent doable, will it begin downloading blocks and advancing its energetic chaintip. So long as one in every of our node’s friends is sincere and caught up, we’d already be on our solution to the precise chaintip.
A block whose timestamp is older than the median of the 11 previous blocks would merely be rejected on the header sync stage, so we should assume that the attacker is serving a blockchain that could be a week previous.
If our node have been eclipsed and all of its friends have been providing solely a chaintip that’s older than every week, our node would synchronize that chaintip. Our node would stay in “initialblockdownload” state, as that solely disables as soon as the timestamp of the node’s energetic tip is not more than 24 hours up to now. This might e.g. trigger the pockets GUI to show a warning that the node will not be caught up. The node would additionally begin making further connections as a consequence of not making progress. If it finds any sincere peer, it’ll proceed synchronizing in the direction of the precise finest chain. If the eclipse assault persists, it’ll stall, however stay in IBD.
