Disabling SELINUX

sometimes i try to connect to MySQL server in CentOS 5 machine, but i have problem can't connect MySQL, i don't understand why, i feel this is coused by not opened the port off MySQl, and i don't know how to open the port, i remember firewall in linux is SElinux and this is my target to disable, with this step;
1. Open File : /etc/selinux/config
2. Change value SELINUX=enforcing to SELINUX=permissive or SELINUX=disable
3. Reboot the machine

and my server has connected.

here to disabling SELinux on Ubuntu

1.cd /boot/grub
2.vi grub.conf This will edit the grub.conf file.
3. Look for the line starting with "kernel" and add "selinux=0" at the end. The line will look similar to this:
kernel /boot/vmlinuz-2.4.20-selinux-2003040709 ro root=/dev/hda1 nousb selinux=0

Save the grub.conf file and reboot the server. Once the server has been rebooted, SELinux is disabled.