How to mount iso-image of the CD drive in FreeBSD

In /boot/loader.conf add vn_load = “YES” or load by the hands kldload vn.ko

mount:

 vnconfig /dev/vn0c /home/user/cdrom.iso
mount -t cd9660 /dev/vn0c /mnt

unmount:

umount /mnt
vnconfig -u /dev/vn0c