enable
configure terminal
no ip domain-lookup
service password-encryption
hostname R2-DHCP
enable secret class
line console 0
password cisco
login
logging synchronous
exit
line vty 0 4
password cisco
login
exit
banner motd #Unauthorized access prohibited#
service dhcp
ip dhcp pool VLAN_A_POOL
network 192.168.1.0 255.255.255.0
default-router 192.168.1.1 
ip dhcp pool VLAN_B_POOL
network 192.168.2.0 255.255.255.0
default-router 192.168.2.1 
ip dhcp excluded-address 192.168.1.1
ip dhcp excluded-address 192.168.2.1
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
interface g0/1
ip address 172.16.1.1 255.255.255.0
no shutdown
exit
interface g0/0
ip address 10.1.1.1 255.255.255.252
no shutdown
exit
ip route 0.0.0.0 0.0.0.0 <INT R3>
interface Tunnel0
ip address 172.16.12.1 255.255.255.252
tunnel source 10.1.1.1    
tunnel destination 10.2.2.1
no shutdown
exit
router ospf 1
network 172.16.1.0 0.0.0.255 area 0 
network 172.16.12.0 0.0.0.3 area 0
end
copy running-config startup-config