Yeah, as a proof it is dubious as it doesn't really define what "established" means in this context. The baeldung article is just wrong > The client, in turn,

Yeah, as a proof it is dubious as it doesn't really define what "established" means in this context. The baeldung article is just wrong > The client, in turn, receives the delayed ACK and assumes that it refers to the last sent SYN message ACKs have acknowledgement numbers, so this sort of confusion can not happen.