Why does connect() succeed even before my server did an accept()?
Answer / chaitanya
Once you have done a listen() call on your socket, the kernel is primed to accept connections on it. The usual UNIX implementation of this works by immediately completing the SYN handshake for any incoming valid SYN segments (connection attempts), creating the socket for the new connection, and keeping this new socket on an internal queue ready for the accept() call. So the socket is fully open before the accept is done.
The other factor in this is the 'backlog' parameter for listen(); that defines how many of these completed connections can be queued at one time. If the specified number is exceeded, then new incoming connects are simply ignored (which causes them to be retried).
| Is This Answer Correct ? | 0 Yes | 0 No |
Why does it take so long to detect that the peer died?
Can a socket have multiple ports?
When should I use shutdown()?
Why does connect() succeed even before my server did an accept()?
How many sockets can a cpu have?
What is socket address?
How do unix sockets work?
How can I set the timeout for the connect() system call?
How can my client work through a firewall/proxy server?
How does a socket work?
How should I choose a port number for my server?
How do I get the port number for a given service?