To test the configuration, you can start with a machine with a hardware address that is not 52:54:00:12:34:59. Make sure the NIC of the client machine is configured to use DHCP to get its IP address. This NIC should get an IP address somewhere from 10.0.2.32 to 10.0.2.63.
Next, try it with another NIC that has a MAC address of 52:54:00:12:34:59 configured to acquire its IP address via DHCP. This NIC should get the IP address of 10.0.2.25.
Alternatively, you can also change the DHCP server configuration to assign the static IP address differently (change the host definition to use a different MAC address). If you do this, you need to restart the DHCP server after the configuration file is changed.
Then you need to release the DHCP lease on the client side. This can be done with “dhclient -r”. Then the client can require its IP address using “dhclient eth0” (without eth0, it will try to acquire IP addresses from all interfaces marked as dhcp in /etc/network/interfaces).
You should also check the fully qualified domain name of the client. Because we set up the domain name in the DHCP configuration file, the client should report its FQDN accordingly. Use “hostname --fqdn” to see the fully qualified domain name.