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Which of the following system calls results in the sending of SYN packets?

  1. $\textsf{socket}$

  2. $\textsf{bind}$

  3. $\textsf{listen}$

  4. $\textsf{connect}$

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Very nicely explained here!


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4 Answers

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Best answer

Answer is (D).

  • $\textsf{socket()}$   creates a new socket of a certain socket type, identified by an integer number, and allocates system resources to it.
  • $\textsf{bind()}$  is typically used on the server side, and associates a socket with a socket address structure, i.e. a specified local port number and IP address.
  • $\textsf{listen()}$ is used on the server side, and causes a bound TCP socket to enter listening state.
  • $\textsf{connect()}$ is used on the client side, and assigns a free local port number to a socket. In case of a TCP socket, it causes an attempt to establish a new TCP connection.

When $\textsf{connect()}$ is called by client, following three way handshake happens to establish the connection in TCP.

  1. The client requests a connection by sending a SYN (synchronize) message to the server.
  2. The server acknowledges this request by sending SYN-ACK back to the client.
  3. The client responds with an ACK, and the connection is established.
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The typical set of system calls on both the machines in a connection-oriented setup is shown in given flowchart.

  • accept() is used on the server side. It accepts a received incoming attempt to create a new TCP connection from the remote client, and creates a new socket associated with the socket address pair of this connection.
  • write() and read(), are used for sending and receiving data to/from a remote socket.
  • close() causes the system to release resources allocated to a socket. In case of TCP, the connection is terminated..
  • source:
Nice Thank you !
0 votes
Connect is used for connection establishment . In connection establishment, first sender will send  SYN flag-synchronization flag which is used to synchronize and tell the receiver that sender is interested in connection establishment.
0 votes
To form a new TCP connection, we use CONNECT system call.
–7 votes
ans b)

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It is connect !

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