$ ./dhtest --help
Usage: ./dhtest [ options ]
  -m mac_address
  -N					# always use interface's MAC address in Ethernet frame
  -r, --release				# Releases obtained DHCP IP for corresponding MAC
  -L, --option51-lease_time [ Lease_time ] # Option 51. Requested lease time in secondes
  -I, --option50-ip	[ IP_address ]	# Option 50 IP address on DHCP discover
  -o, --option60-vci	[ VCI_string ]	# Vendor Class Idendifier string
  -h, --option12-hostname [ hostname_string ] # Client hostname string
  -c, --custom-dhcp-option [ option_format ] # option_format - option_number,type_of_option_value(str|num|hex|ip),option_value
  -v, --vlan		[ vlan_id ]	# VLAN ID. Range(1 - 4094)
  -t, --tos		[ TOS_value ]	# IP header TOS value
  -i, --interface	[ interface ]	# Interface to use. Default eth0
  -T, --timeout		[ cmd_timeout ]	# Command returns within specified timout in seconds
  -b, --bind-ip				# Listens on the obtained IP. Supported protocols - ARP and ICMP
  -k, --bind-timeout	[ timeout ]	# Listen timout in seconds. Default 3600 seconds
  -f, --bcast_flag			# Sets broadcast flag on DHCP discover and request
  -d, --fqdn-domain-name   [ fqdn ]	# FQDN domain name to use
  -n, --fqdn-server-not-update		# Sets FQDN server not update flag
  -s, --fqdn-server-update-a		# Sets FQDN server update flag
  -p, --padding				# Add padding to packet to be at least 300 bytes
  -P, --port		[ port ]	# Use port instead of 67
  -g, --giaddr		[ giaddr ]	# Use giaddr instead of 0.0.0.0
  -u, --unicast		[ ip ]		# Unicast request, IP is optional. If not specified, the interface address will be used. 
  -a, --nagios				# Nagios output format. 
  -S, --server		[ address ]	# Use server address instead of 255.255.255.255
  -j, --json				# Set the output format to json
  -D, --decline				# Declines obtained DHCP IP for corresponding MAC
  -V, --verbose				# Prints DHCP offer and ack details
  dhtest version 1.5

./dhtest -i eth1 -T 10 -m 2c:c4:07:00:06:a0
DHCP discover sent	 - Client MAC : 2c:c4:07:00:06:a0
DHCP offer received	 - Offered IP : 192.168.76.170
DHCP request sent	 - Client MAC : 2c:c4:07:00:06:a0
DHCP ack received	 - Acquired IP: 192.168.76.170

                 host PC
+-----------------------------------------+
|* eth: 192.168.70.1/255.255.128.0        |
|* tftpd32-dhcp                           |
+-----------------------------------------+
|* VM(eth1): 192.168.70.2/255.255.255.128 |
|* dhtest                                 |
+-----------------------------------------+

$ route -n
Kernel IP routing table
Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
0.0.0.0         192.168.70.1    0.0.0.0         UG    0      0        0 eth1
10.0.2.0        0.0.0.0         255.255.255.0   U     0      0        0 eth0
192.168.0.0     0.0.0.0         255.255.128.0   U     0      0        0 eth1 

$ sudo ./auto_dhctest.sh