Several limits in the Linux kernel are low and can be modified. Some can be changed through the /proc file system, and others require recompiling the kernel.
Note: The /proc file system is virtual; that is, it does not exist physically on the disk. Instead, it serves as an interface into the Linux kernel. Because it does not exist, your input values are lost on restart. Therefore, place changes that you want to make to the /proc file system in the /etc/rc.d/rc.local file on RedHat or in the /etc/rc.config file on SUSE. Changes are then always activated at restart.
Some recommendations follow:
echo 32768 > /proc/sys/fs/file-max
echo 65536 > /proc/sys/fs/inode-max
echo 32768 61000 > /proc/sys/net/ipv4/ip_local_port_range
If you decide to rebuild your kernel, enable only those options that you definitely need. If you do not need a specific daemon, do not run it.