DRHD: handling fault status regf0003c80 Kernel panic -not syncing : DMAR hardware

• Power on the system and press tab at boot menu
• Pass boot parameter to the kernel

        intel_iommu=off

• boot the system
• After booting successufully, edit grub.conf for permanent setting.

"Reverse Mapping Checking: Possible Break-in Attempt!" Error with SSH

The reverse DNS had not been set up for the server.

Add remote host to your /etc/hosts file.

Gtk-warnning ** : can not open display or ** WARNING ** can not open display

The problem is with two environment variables DISPLAY and XAUTHORITY

$ su -

password:

# export DISPLAY=0:0

# export XAUTHORITY=/home/username/.Xauthority

to verify, run a graphical program from terminal. e.g.;

# xeyes