7.4.1 Packet Tracer – Implement DHCPv4 – Instructions Answer

R2(config)#ip dhcp excluded-address 192.168.10.1 192.168.10.10
R2(config)#ip dhcp excluded-address 192.168.30.1 192.168.30.10

R2(config)#ip dhcp pool R1-LAN
R2(dhcp-config)#network 192.168.10.0 255.255.255.0
R2(dhcp-config)#default-router 192.168.10.1
R2(dhcp-config)#dns-server 192.168.20.254

R2(config)#ip dhcp pool R3-LAN
R2(dhcp-config)#network 192.168.30.0 255.255.255.0
R2(dhcp-config)#default-router 192.168.30.1
R2(dhcp-config)#dns-server 192.168.20.254

R1(config)#interface g0/0
R1(config-if)#ip helper-address 10.1.1.2

R3(config)#interface g0/0
R3(config-if)#ip helper-address 10.2.2.2

R2(config)#interface g0/1
R2(config-if)#ip address dhcp
R2(config-if)#no shutdown

! ==============================================================
!--- 7.4.1 Packet Tracer - Implement DHCPv4
!--- ANSWER SCRIPT FOR ROUTER R1
!--- Usage: from the console (or a Telnet/SSH session, if already reachable) on R1, enter privileged EXEC mode with "enable", then paste this whole file. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. This script assumes R1's LAN/WAN interfaces are already up and addressed from a previous activity - it only adds the DHCP relay command this lab actually asks for.
!--- R1's LAN (192.168.10.0/24) has no local DHCP server - PC1 needs to reach the DHCP pool configured on R2, across the R1-R2 serial link.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Part 2: Configure the DHCP relay (helper address) on the LAN interface
! --------------------------------------------------------------

!--- Points at R2's S0/0/0 address (the serial interface facing R1) - DHCP broadcasts from PC1 get relayed there and processed by R2's R1-LAN pool.
interface GigabitEthernet0/0
 ip helper-address 10.1.1.2

end

! --------------------------------------------------------------
!--- Operational habit (not explicitly required by this lab): save to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config

! ==============================================================
!--- Verification:
!---   R1# show running-config interface g0/0 -> shows "ip helper-address 10.1.1.2"
!---   From PC1, set NIC to DHCP -> should receive an address in 192.168.10.11-254 (per the excluded range configured on R2), gateway 192.168.10.1, DNS 192.168.20.254
! ==============================================================

! ==============================================================
!--- 7.4.1 Packet Tracer - Implement DHCPv4
!--- ANSWER SCRIPT FOR ROUTER R2
!--- Usage: from the console (or a Telnet/SSH session, if already reachable) on R2, enter privileged EXEC mode with "enable", then paste this whole file. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. This script assumes R2's LAN/WAN interfaces are already up and addressed from a previous activity (except G0/1, which this lab brings up via DHCP) - it only adds the DHCP server and DHCP client commands this lab actually asks for.
!--- R2 plays two DHCP roles here: it's the DHCP SERVER for both R1's and R3's remote LANs (reached via relay), and it's a DHCP CLIENT itself on G0/1, getting its own address from the ISP.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Part 1, Step 1: Exclude statically-assigned addresses from both pools
! --------------------------------------------------------------

!--- Excludes the first 10 addresses of each remote LAN so the DHCP pools never hand these out - "all other addresses should be available" per the Instructions.
ip dhcp excluded-address 192.168.10.1 192.168.10.10
ip dhcp excluded-address 192.168.30.1 192.168.30.10

! --------------------------------------------------------------
!--- Part 1, Step 2: Create the DHCP pool for the R1 LAN
! --------------------------------------------------------------

!--- Pool name must be exactly "R1-LAN" (case-sensitive) for grading.
ip dhcp pool R1-LAN
 network 192.168.10.0 255.255.255.0
 default-router 192.168.10.1
 dns-server 192.168.20.254

! --------------------------------------------------------------
!--- Part 1, Step 3: Create the DHCP pool for the R3 LAN
! --------------------------------------------------------------

!--- Pool name must be exactly "R3-LAN" (case-sensitive) for grading.
ip dhcp pool R3-LAN
 network 192.168.30.0 255.255.255.0
 default-router 192.168.30.1
 dns-server 192.168.20.254

! --------------------------------------------------------------
!--- Part 3: Configure R2 itself as a DHCP client toward the ISP, then activate it
! --------------------------------------------------------------

!--- G0/1 pulls its own address from the ISP's DHCP server instead of a static one. The Instructions call out "Activate the interface" as its own separate step (3.2) - "no shutdown" is required here since the interface starts administratively down; without it, DHCP negotiation never begins.
interface GigabitEthernet0/1
 ip address dhcp
 no shutdown

end

! --------------------------------------------------------------
!--- Operational habit (not explicitly required by this lab): save to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config

! ==============================================================
!--- Verification:
!---   R2# show ip dhcp binding    -> shows leases for PC1 (192.168.10.11) and PC2 (192.168.30.11)
!---   R2# show ip interface brief -> G0/1 shows an address learned from the ISP (use Packet Tracer's "Fast Forward Time" to speed this up)
!---   From PC1, set NIC to DHCP   -> receives 192.168.10.11+, gateway 192.168.10.1, DNS 192.168.20.254
!---   From PC2, set NIC to DHCP   -> receives 192.168.30.11+, gateway 192.168.30.1, DNS 192.168.20.254
! ==============================================================

! ==============================================================
!--- 7.4.1 Packet Tracer - Implement DHCPv4
!--- ANSWER SCRIPT FOR ROUTER R3
!--- Usage: from the console (or a Telnet/SSH session, if already reachable) on R3, enter privileged EXEC mode with "enable", then paste this whole file. Every line beginning with "!" is a comment; IOS ignores it, so pasting a comment by accident is harmless. This script assumes R3's LAN/WAN interfaces are already up and addressed from a previous activity - it only adds the DHCP relay command this lab actually asks for.
!--- R3's LAN (192.168.30.0/24) has no local DHCP server - PC2 needs to reach the DHCP pool configured on R2, across the R3-R2 serial link.
! ==============================================================

enable
configure terminal

! --------------------------------------------------------------
!--- Part 2: Configure the DHCP relay (helper address) on the LAN interface
! --------------------------------------------------------------

!--- Points at R2's S0/0/1 address (the serial interface facing R3) - DHCP broadcasts from PC2 get relayed there and processed by R2's R3-LAN pool.
interface GigabitEthernet0/0
 ip helper-address 10.2.2.2

end

! --------------------------------------------------------------
!--- Operational habit (not explicitly required by this lab): save to NVRAM. (Press Enter when prompted for the destination filename.)
! --------------------------------------------------------------
copy running-config startup-config

! ==============================================================
!--- Verification:
!---   R3# show running-config interface g0/0 -> shows "ip helper-address 10.2.2.2"
!---   From PC2, set NIC to DHCP -> should receive an address in 192.168.30.11-254, gateway 192.168.30.1, DNS 192.168.20.254
! ==============================================================