Program completed but TCP sockets remain for a while

[benvenuto]

Hi !

In my program I close all TCP sockets before exiting it.
But nevertheless remain the sockets in TIME_WAIT state for a while.
('netstat -na' shows me that.)

What I want is to ensure that all my TCP sockets get removed
from the system immediately when I stop my process.

Is it possible and how?

[ticuvina]

I can be wrong, but I think, After close connection command executed, Linux OS can't close connection immediately, it must take a short time to close, that is reason when typing 'netstat -na' you saw TIME_WAIT state.

[cbogdan]

The close of socket goes through the TIME_WAIT state. The duration of TIME_WAIT state is twice the maximum segment lifetime (MSL is the maximum amount of time that any given IP datagram can stay in a network). The recommended value of MSL (RFC 1122) is 2 minutes, but Berkeley implementations use 30 seconds. So, the duration of the TIME_WAIT is between 1 and 4 minutes. But in fact you have to take also into consideration the IPv4 TTL field with a maximum value of 255.