To configure custom DHCP options for a VM use the following command adapted
to your needs:

$ VBoxManage dhcpserver modify \
    --netname test-0 --options --vm "Test Client" --slot 0 \
    --id 0 --value "224=c0:a8:02:01:c0:a8:02:02" \
    --id 0 --value "225=0:0"

Note that custom DHCP options must be specified with ID 0 and the actual
number in the value. This has technical reasons which may change in future
VirtualBox releases.


It corresponds to the following bit of ISC 'dhcpd.conf':

option sample1 code 224 = array of ip-address;
option sample2 code 225 = array of integer 8;

...
    option sample1 192.168.2.1,192.168.2.2;
    option sample2 0,0;
...