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can someone help me to solved my router 1 as relay agent dhcp.Currently user 5 that connect from switch 1 is not being able to get dhcp ip address. My router 2 as dhcp server pool and user 3 ,4 is successfully get the dhcp ip.The problem from user 5 that not getting dhcp ip from relay agent R1.

R2-dhcp server

ip dhcp excluded-address 192.168.30.1 192.168.30.10
ip dhcp pool R2-LAN30
network 192.168.30.0 255.255.255.0
default-router 192.168.30.1
dns-server 172.21.50.100

R1-dhcp relay agent

interface GigabitEthernet0/0
ip address 10.10.20.2 255.255.255.252
duplex auto
speed auto
!
interface GigabitEthernet1/0
ip address 10.10.20.9 255.255.255.252
duplex auto
speed auto
!
interface FastEthernet2/0
no ip address
duplex auto
speed auto
!
interface FastEthernet2/0.10
encapsulation dot1Q 10
ip address 192.168.10.1 255.255.255.0
!
interface FastEthernet2/0.20
encapsulation dot1Q 20
ip address 192.168.20.1 255.255.255.0
!
interface FastEthernet3/0
ip address 192.168.30.2 255.255.255.0
ip helper-address 10.10.20.10
duplex auto
speed auto
!

R1 -int ip brief

R1#show ip int brief
Interface IP-Address OK? Method Status Protocol 
GigabitEthernet0/0 10.10.20.2 YES manual up up 
GigabitEthernet1/0 10.10.20.9 YES manual up up 
FastEthernet2/0 unassigned YES manual up up 
FastEthernet2/0.10 192.168.10.1 YES manual up up 
FastEthernet2/0.20 192.168.20.1 YES manual up up 
FastEthernet3/0 192.168.30.2 YES manual up up 
Serial4/0 unassigned YES NVRAM administratively down down 
Serial5/0 unassigned YES NVRAM administratively down down

R2 -int ip brief

R2#sh ip int brief
Interface IP-Address OK? Method Status Protocol 
GigabitEthernet0/0 10.10.20.6 YES manual up up 
GigabitEthernet1/0 10.10.20.10 YES manual up up 
FastEthernet2/0 192.168.30.1 YES manual up up 
FastEthernet3/0 unassigned YES NVRAM administratively down down 
Serial4/0 unassigned YES NVRAM administratively down down 
Serial5/0 unassigned YES NVRAM administratively down down

enter image description here

enter image description here Step 7: Configure DHCPv4 Configure a R2 as a DHCP Server to enable IP address can be assigned dynamically to user 3 and user 4 which IP address is VLAN 30. Make sure you exclude the first 10 addresses from the R2 LAN 192.168.30.0/24. Create a DHCP pool named R2-LAN 30 (case-sensitive). Configure R1 as a DHCP relay agent so that user 5 also can be assigned IP address dynamically.Verify DHCP bindings using command R2# show ip dhcp binding.Verify that User 3 and user 4 are assigned with the correct IP address and can ping each other and all other devices.

This is my lab.pkt

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  • Please, never use images for text. See this Meta answer.
    – Ron Maupin ♦
    Jul 21, 2022 at 2:06
  • Again, please remove the images of the text and replace it with the actual text. I cannot copy the text from the images to make corrections, and I am not going to completely retype it for you.
    – Ron Maupin ♦
    Jul 21, 2022 at 2:19
  • sorry, i re-edit.
    – Nurul Ain
    Jul 21, 2022 at 2:34
  • Please also use proper formatting for pasted console text which makes it much easier to read - use the editor's {} function or just hit Ctrl-k.
    – Zac67 ♦
    Jul 21, 2022 at 5:24

1 Answer 1

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You do not have an IPv4 address on R1 FastEthernet 3/0. The interface cannot source DHCP to the server, nor could the server reply to the interface.

The DHCP server will determine which DHCP pool to use based on the interface network, but the interface has no network. The only DHCP pool you show is for an interface on R2. Routers need different networks, and you cannot have the same network on the R1 and R2 interfaces that are separated by layer-3.

You need to assign a network to R1 FastEthernet 3/0 and create a DHCP pool on R2 for the R1 FastEthernet 3/0 network.

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  • ok i just adding the network on R1 fastEthernet 3/0 192.168.30.2 ,but still cannot get the dhcp ip for user 5.
    – Nurul Ain
    Jul 21, 2022 at 2:18
  • Read what I wrote. You cannot have the same network on different router interfaces that are separated by layer-3. You need a different network on the R1 interface.
    – Ron Maupin ♦
    Jul 21, 2022 at 2:21
  • i already attach my actual topology, i dont understand to use diffrent network on the R1 interface,because the topology show that only 192.168.30.0/24 for r1 and r2.
    – Nurul Ain
    Jul 21, 2022 at 2:43

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