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 the parameter below 60000
usr/sbin/ndd -set /dev/tcp tcp_time_wait_interval 60000
If your system is not exhibiting the symptoms mentioned, and if you are not well-versed in tuning the TCP protocol, do not change the above parameter.