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Hack Security Pro.pdf - Index of

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Third step<br />

Illustration 3: ACK<br />

To conclude this connection, machine A, in response to the SYN/ACK sent by B, sends an ACK back<br />

to it (only the ACK bit is initialized). The packet still contains an ISN and an ACK; the value <strong>of</strong> the ISN<br />

is the ACK number <strong>of</strong> the previous packet sent by B, and for ACK it is the sequence number <strong>of</strong> the<br />

previous packet sent by B + 1 (during the connection initialization).<br />

Later on, the ACK sent by a local machine to a remote machine will be made up <strong>of</strong> the sequence<br />

number sent by the remote machine in its last packet, to which will be added the number <strong>of</strong> data bytes<br />

received during this transmission.<br />

The <strong>Hack</strong>ademy DMP -71/209- SYSDREAM

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