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+23 votes

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

  1. socket

  2. bind

  3. listen

  4. connect

in Computer Networks by | 4.9k views

Very nicely explained here!

3 Answers

+54 votes
Best answer

Answer is (D).

socket()   creates a new socket of a certain socket type, identified by an integer number, and allocates system resources to it.
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.
listen() is used on the server side, and causes a bound TCP socket to enter listening state.
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 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.

edited by

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.
–7 votes
ans b)
It is connect !

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