It worked. Below is my grub.cfg
menuentry "Install Ubuntu" { set gfxpayload=keep linux /ubuntu-installer/amd64/linux live-installer/net-image=http://192.168.1.1/ubuntu/install/filesystem.squashfs hostname=unassigned netcfg/choose_interface=auto gfxpayload=800x600x16,800x600 --- auto=true url=http://192.168.1.1/preseed.cfg quiet initrd /ubuntu-installer/amd64/initrd.gz }
It worked.
Below is my grub.cfg
menuentry "Install Ubuntu" { installer/ amd64/linux live-installer/ net-image=http:// 192.168. 1.1/ubuntu/ install/ filesystem. squashfs hostname=unassigned netcfg/ choose_ interface= auto gfxpayload= 800x600x16, 800x600 --- auto=true url=http:// 192.168. 1.1/preseed. cfg quiet installer/ amd64/initrd. gz
set gfxpayload=keep
linux /ubuntu-
initrd /ubuntu-
}