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i am not getting dhcp ip add from the server the configuration follows below can any one help me please

i am not getting ip add from the dhcp server ,

if i am adding the dhcp server to vlan 50 then only i am getting ip add

i am having two vlan 50 and vlan 51

so can any one help me what is the isssue i am attaching my network diagram and configuration

core switch configuration

Switch#sho run

Building configuration...

Current configuration : 2964 bytes

!

version 12.2

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Switch

!

!

!

!

!

ip routing

!

!

!

!

!

!

!

!

!

!

!

!

!

!

interface FastEthernet0/1

channel-group 1 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/2

channel-group 1 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/3

channel-group 1 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/4

channel-group 1 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/5

channel-group 2 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/6

channel-group 2 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/7

channel-group 2 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/8

channel-group 2 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/9

channel-group 3 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/10

channel-group 3 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/11

channel-group 3 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/12

channel-group 3 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/13

channel-group 4 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/14

channel-group 4 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/15

channel-group 4 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/16

channel-group 4 mode on

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface FastEthernet0/17

!

interface FastEthernet0/18

!

interface FastEthernet0/19

!

interface FastEthernet0/20

!

interface FastEthernet0/21

!

interface FastEthernet0/22

!

interface FastEthernet0/23

!

interface FastEthernet0/24

!

interface GigabitEthernet0/1

!

interface GigabitEthernet0/2

!

interface Port-channel 1

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface Port-channel 2

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface Port-channel 3

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface Port-channel 4

switchport trunk encapsulation dot1q

switchport mode trunk

!

interface Vlan1

no ip address

shutdown

!

interface Vlan50

ip address 192.168.50.1 255.255.255.0

ip helper-address 192.168.50.2

!

interface Vlan51

ip address 192.168.51.1 255.255.255.0

ip helper-address 192.168.50.2

!

ip classless

!

!

!

!

!

!

!

line con 0

line vty 0 4

login

!

!

!

end

LAYER 2 SW-1

Building configuration...

Current configuration : 1834 bytes

!

version 12.2

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Switch

!

!

!

interface FastEthernet0/1

channel-group 1 mode on

switchport mode trunk

!

interface FastEthernet0/2

channel-group 1 mode on

switchport mode trunk

!

interface FastEthernet0/3

channel-group 1 mode on

switchport mode trunk

!

interface FastEthernet0/4

channel-group 1 mode on

switchport mode trunk

!

interface FastEthernet0/5

switchport access vlan 50

description DHCP SERVER

!

interface FastEthernet0/6

switchport access vlan 50

!

interface FastEthernet0/7

switchport access vlan 50

!

interface FastEthernet0/8

switchport access vlan 50

!

interface FastEthernet0/9

switchport access vlan 50

!

interface FastEthernet0/10

switchport access vlan 50

!

interface FastEthernet0/11

switchport access vlan 50

!

interface FastEthernet0/12

switchport access vlan 50

!

interface FastEthernet0/13

switchport access vlan 50

!

interface FastEthernet0/14

switchport access vlan 50

!

interface FastEthernet0/15

switchport access vlan 50

!

interface FastEthernet0/16

switchport access vlan 50

!

interface FastEthernet0/17

switchport access vlan 50

!

interface FastEthernet0/18

switchport access vlan 50

!

interface FastEthernet0/19

switchport access vlan 50

!

interface FastEthernet0/20

switchport access vlan 50

!

interface FastEthernet0/21

switchport access vlan 50

!

interface FastEthernet0/22

switchport access vlan 50

!

interface FastEthernet0/23

switchport access vlan 50

!

interface FastEthernet0/24

switchport access vlan 50

!

interface GigabitEthernet1/1

!

interface GigabitEthernet1/2

!

interface Port-channel 1

!

interface Vlan1

no ip address

shutdown

!

interface Vlan50

no ip address

ip helper-address 192.168.50.2

!

!

line con 0

!

line vty 0 4

login

line vty 5 15

login

!

!

end

LAYER 2 SW-2

Building configuration...

Current configuration : 1834 bytes

!

version 12.2

no service timestamps log datetime msec

no service timestamps debug datetime msec

no service password-encryption

!

hostname Switch

!

!

!

interface FastEthernet0/1

channel-group 2 mode on

switchport mode trunk

!

interface FastEthernet0/2

channel-group 2 mode on

switchport mode trunk

!

interface FastEthernet0/3

channel-group 2 mode on

switchport mode trunk

!

interface FastEthernet0/4

channel-group 2 mode on

switchport mode trunk

!

interface FastEthernet0/5

switchport access vlan 51

!

interface FastEthernet0/6

switchport access vlan 51

!

interface FastEthernet0/7

switchport access vlan 51

!

interface FastEthernet0/8

switchport access vlan 51

!

interface FastEthernet0/9

switchport access vlan 51

!

interface FastEthernet0/10

switchport access vlan 51

!

interface FastEthernet0/11

switchport access vlan 51

!

interface FastEthernet0/12

switchport access vlan 51

!

interface FastEthernet0/13

switchport access vlan 51

!

interface FastEthernet0/14

switchport access vlan 51

!

interface FastEthernet0/15

switchport access vlan 51

!

interface FastEthernet0/16

switchport access vlan 51

!

interface FastEthernet0/17

switchport access vlan 51

!

interface FastEthernet0/18

switchport access vlan 51

!

interface FastEthernet0/19

switchport access vlan 51

!

interface FastEthernet0/20

switchport access vlan 51

!

interface FastEthernet0/21

switchport access vlan 51

!

interface FastEthernet0/22

switchport access vlan 51

!

interface FastEthernet0/23

switchport access vlan 51

!

interface FastEthernet0/24

switchport access vlan 51

!

interface GigabitEthernet1/1

!

interface GigabitEthernet1/2

!

interface Port-channel 2

!

interface Vlan1

no ip address

shutdown

!

interface Vlan51

no ip address

ip helper-address 192.168.50.2

!

!

line con 0

!

line vty 0 4

login

line vty 5 15

login

!

!

end

5 Replies 5

cadet alain
VIP Alumni
VIP Alumni

Hi,

For DHCP relay agent to work you must enable the DHCP service with service DHCP global configuration mode command and your DHCP server must have a route for the IP of the interface where ip helper-address is configured and of course you must have the corresponding pool configured.

Regards

Alain

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InayathUlla Sharieff
Cisco Employee
Cisco Employee

Hi Mohammed,

Yes you are correct you need to add the command ip helper address under vlan on which you need to recieve the same.

Couple of things to be check:

ip dhcp server X.X.X.X  >>> I hope this is there

service dhcp enable>>>> SErvice is enabled.

For example:

PC-----Switch----Router

PC---Obtain ip addres--------Port in access vlan 50------Switch( Int vlan 50, ip helper address 1.1.1.1)----router (DHCP server).

Ref:

http://www.cisco.com/en/US/docs/ios-xml/ios/ipaddr_dhcp/configuration/12-4t/config-dhcp-server.html

HTH

REgards

Inayath

service dhcp enable should be configure on all the switches or just core switch

i am having 1 core 4507 to which rem 4 layer 2 switch are connected

Hi,

it should be enabled on the switch acting as a Relay agent so your core switch.

Regards

Alain

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