Grokking Computer Networking for Software Engineers/

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TCP Header Flags

TCP Header Flags

In the last lesson, we discussed eight fields of the TCP header. Let's now discuss the last few!

We'll cover the following...

TCP headers have eight 1-bit flags that are imperative to signaling in the protocol.

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Each 1-bit flag is crucial to make the protocol work.
Each 1-bit flag is crucial to make the protocol work.

Flags

Let’s have a quick look at what each flag is meant for.

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The eight flags used in TCP headers.
The eight flags used in TCP headers.

The first four discussed below, namely ACK, RST, SYN, and FIN are used in the establishment, maintenance, and tear-down of a TCP connection.

ACK

This flag is set to 11 in a segment to acknowledge a segment that was received previously. This is an important ...