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DHCP request failed!!

Nicky Sam
Level 1
Level 1

dear all,

I'm fresher network student & studying about DHCP (through Relay agent)
I routed, set up trunking & host could be able to ping to DHCP server (when setup IP static) but I have no idea the reason why it dind't worked
Aprreciate your all comments & suggestion!!

 

R2: DHCP server

R2(config)#ip dhcp pool VLAN10

R2(dhcp-config)#network 172.16.10.0 255.255.255.0

R2(dhcp-config)#def 172.16.10.1

R2(dhcp-config)#dns 8.8.8.8

 

R1: Relay Agent

R1(config)#int f0/1.10

R1(config-subif)#en dot 10

R1(config-subif)#ip add 172.16.10.1 255.255.255.0

 

R1(config)#int f0/1.20

R1(config-subif)#en dot 20

R1(config-subif)#ip add 172.16.20.1 255.255.255.0


R1(config)#int f0/1

R1(config-if)#ip help 192.168.1.2

Switch:

Switch(config)#int f0/1

Switch(config-if)#sw mo tru

Switch(config)#vlan 10

Switch(config-vlan)#name VLAN10

 

Switch(config)#vlan 20

Switch(config-vlan)#name VLAN20

 

Switch(config)#int f0/3

Switch(config-if)#sw acc vlan 10

 

Switch(config)#int f0/2

Switch(config-if)#sw acc vlan 20

 

 

1 Accepted Solution

Accepted Solutions

Hello,

make sure you have the below configured:

service dhcp

ip dhcp excluded-address 172.16.10.1

And on the access switchports (the ones where your clients are connected to):

spanning-tree portfast

In addition, configure the helper address on the subinterfaces as well. That said, you currently only have a DHCP pool for VLAN 10, but I guess you are aware of that.

View solution in original post

2 Replies 2

Hello,

make sure you have the below configured:

service dhcp

ip dhcp excluded-address 172.16.10.1

And on the access switchports (the ones where your clients are connected to):

spanning-tree portfast

In addition, configure the helper address on the subinterfaces as well. That said, you currently only have a DHCP pool for VLAN 10, but I guess you are aware of that.

thanks, it worked.
I missed config ip helper on sub interface :)