TCP 3-way handshake

TCP 3-Way Handshake Explained

Imagine you’re a delivery person (Client) who wants to start a chat with a friend (Server). But instead of just ringing the doorbell, you both follow a fancy, overly polite ritual before the conversation starts.

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?Step 1: SYN – “Knock, Knock!”

• Oluwatosin Dada Client: “Hey 谷歌 , I want to talk to you! ?Here’s my name oluwatosin Dada and a secret handshake starter code: 12345. Are you there?” (Sends a SYN packet with a sequence number: 12345)

Step 2: SYN-ACK – “Who's There?”

• 谷歌 Server: “I hear you! I’ll talk to you, but first, here’s my handshake starter: 67890. Also, I got your starter code 12345 and I’m ready to respond to it.” (Sends a SYN-ACK packet: acknowledges 12345 and includes its own sequence number: 67890)

?Step 3: ACK – “It’s Me!”

• oluwatosin Dada Client: “Thanks! I got your starter code 67890, and now I’m all set to chat. Let’s do this!” (Sends an ACK packet, acknowledging 67890)

Handshake Complete: Let’s Chat!

Now that both parties have exchanged their secret handshakes and are on the same page, they’re ready to start their conversation (data exchange). ??

Dude… What’s the TCP 3-way handshake?

It’s like an overly formal “knock-knock” joke for computers:

Client: Knock, knock!

Server: Who’s there?

Client: It’s me! Now let’s talk!

Both sides are so polite that they double-check everything before saying anything meaningful, like two overly cautious pen pals who confirm every single letter before starting the actual conversation.

What If Something Goes Wrong?

• If the Server doesn’t respond? The Client awkwardly knocks again (resends SYN), then gives up if there’s no answer.
• If the Server responds but the Client doesn’t follow up? The Server waits for a bit and then slams the door (connection timeout).

So next time your device connects to a website or service, imagine a tiny, formal handshake ritual happening behind the scenes. It’s computer etiquette at its finest! Humans could learn from it! ??

Real-World Applications

The 3-way handshake is essential in various scenarios, such as:

• Loading web pages
• Streaming media
• File transfers

Understanding this process is fundamental for networking and cybersecurity professionals to troubleshoot and secure TCP communications.