请帮我看看我的DHCP启动不了

ddns-update-style interim;
ignore clien-updates;

suben 10.0.0.0 netmask 255.0.0.0{
default-lease-time 21600;
max-lease-time 43200;
option routers 10.0.0.1;
option broadcast-address 10.0.0.255;
option subnet-mask 255.0.0.0;
option domain-name "chenzx";
option nis-domain "chenzx";
option domain-name-servers 10.0.1.1;
option time-offset -1800;
option ntp-servers 10.0.1.1;
option netbios-name-servers 10.0.1.1;



range dynamic-bootp 10.0.0.10 10.0.0.200;
}