If your Linux server is opening lots of outgoing network connections, you need to increase local port range. By default range is small. For example a squid proxy server can come under fire if it runs out of ports.
You can use the sysctl command to to modify kernel parameters at runtime. The parameters available are those listed under /proc/sys/. Please note that this hack is only useful for high bandwidth, busy Linux servers or large scale grid servers.
How to find current port range type
Type the following command
$ sysctl net.ipv4.ip_local_port_range
net.ipv4.ip_local_port_range = 32768 61000
Set new local port range
You can set the range with any one of the following command. You must be root user:
# echo 1024 65535 > /proc/sys/net/ipv4/ip_local_port_range
$ sudo sysctl -w net.ipv4.ip_local_port_range="1024 64000"
Finally, edit /etc/sysctl.conf file, to make changes to /proc filesystem permanently i.e. append the following line to your /etc/sysctl.conf file:
# increase system IP port limits
net.ipv4.ip_local_port_range = 1024 65535