If users are experiencing connection refused errors on a heavily loaded server, you can tune the use of network resources on the server.
When a TCP/IP connection is closed, the port is not reused for the duration of tcp_time_wait_interval (default value of 240000 milliseconds). This is to ensure that there are no leftover segments. The shorter the tcp_time_wait_interval, the faster precious network resources are again available. This parameter is changed by executing the following command (do not reduce it below 60000):
usr/sbin/ndd -set /dev/tcp tcp_time_wait_interval 60000
To automatically have this ndd command executed after each system reboot, place it in a file called /etc/init.d/network-tuning and create a link to that file named /etc/rc2.d/S99network-tuning.
If your system is not exhibiting the symptoms mentioned, and if you are not well-versed in tuning the TCP protocol, it is suggested that you do not change the above parameter.