main@main:~$ sudo /etc/init.d/dhcp3-server start
dhcpd self-test failed. Please fix the config file.
The error was: 
/etc/dhcp3/dhcpd.conf line 12: subnet 10.0.0.1 netmask 255.255.255.0: bad subnet number/mask combination.
subnet 10.0.0.1 netmask 255.255.255.0 
                                    ^
Configuration file errors encountered -- exiting
main@main:~$ ipcalc 10.0.0.1 255.255.255.0
Address:   10.0.0.1             00001010.00000000.00000000. 00000001
Netmask:   255.255.255.0 = 24   11111111.11111111.11111111. 00000000
Wildcard:  0.0.0.255            00000000.00000000.00000000. 11111111
=>
Network:   10.0.0.0/24          00001010.00000000.00000000. 00000000
HostMin:   10.0.0.1             00001010.00000000.00000000. 00000001
HostMax:   10.0.0.254           00001010.00000000.00000000. 11111110
Broadcast: 10.0.0.255           00001010.00000000.00000000. 11111111
Hosts/Net: 254                   Class A, Private Internet

main@main:~$