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Does the PSH bit force client to ack

Hi All,

First off, thank you to the awesome community. I have just started my packet analysis journey, and have become quite addicted.

My question is if the server/client sends 1 packet with the push bit set, would this cause the receiver to ack even though 2 packets were not sent? I have seen/read many times that the rule of TCP is ack every other packet, but occasionally in a capture I am looking at the sender will set the psh bit after sending only 1 packet, and the receiver will ack immediately (empty ack). What confuses me is the receiver will then immediately send another packet with data. Wouldn't the rule of TCP prevent an empty ack since only 1 packet was sent, and since the client is sending data, wouldn't it just piggy back off the first ack rather than send an empty ack, then send data?

Thank you, and please let me know if I am not making sense. I will attempt to clarify.