The process of establishing a socket connection 1:client send a SYN request to Server2:server after receiving the request placed in the SYN queue, the maximum value of this half-connection queue is the system parameters Tcp_max_syn_ Backlog definition 3: stored in a semi-connected queue after sending Syn+ack to Client4:client received before sending Syn+ack to the server to complete three handshake, and then server put the connection in the Accept queue, This queue length is defined as the backlog definition size 5 when calling the socket in the program: The application gets a connection by calling accept () to accpetqueue but what happens when the Accpet queue is full? Note: If the Accpet queue is full, Linux will have an exception handling, to determine whether the Tcp_abort_on_overflow system parameter is 1, if it is 1, will be issued to deny the client's termination message and disconnect. But if this parameter is 0, then the pit father, for the overflow queue connection, Linux will not go to it, will continue to establish a normal connection, but in the Accpetqueue no
Analysis of the backlog of connection queues for Linux sockets