I an simulating http client traffic with RAW socket. I send a SYN packet then get the SYN-ACK from the server. Finally I send an ACK+request packet and waits for the response. I noticed that when using wget or curl, the first ACK and the request are sent in two different packets. why is that, and is that relevant to anything?
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I think your question is being answered [here](http://stackoverflow.com/questions/3761276/when-should-i-use-tcp-nodelay-and-when-tcp-cork) – DaSourcerer May 20 '16 at 16:01
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It is because that is the way they work, and no it isn't relevant to anything. – user207421 May 21 '16 at 08:40
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A client application that uses a TCP socket typically calls socket() then connect() then send(). The connect() function establishes the TCP connection, and to do this the TCP protocol requires 3 packets: SYN, SYN+ACK, ACK. After that the send() call sends the first data. Therefore the ACK and data are sent separately.
I think your packet flow probably does satisfy the TCP protocol (see https://www.rfc-editor.org/rfc/rfc793), but it is unusual.
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