Sometimes the server may not respond to anything but ping.
In this case the system administrator has to reboot the server using Reset button.
But the simpler way to do it is to use the kernel module ipt_sysrq (Linux only).
The way it works is described here.

To use the features of this module through the panel DediKit at first you should compile and download this module on the server, then in the settings of the panel the variable reboot_password should be filled making sure that the value of the variable coincides with the password from the setting ipt_SYSRQ.

After that in the section Reboot the button Reboot appears, pressing this button you will start the reboot of the dedicated server.