DHCP on specific Vlan

[grahamhyland]

Hello,

I have a 3650 on a site with many vlans, I want to make the switch a dhcp server and alow clients on vlan 7 to avail of the dhcp server.

I do not want to affect clinets on vlan 20 that use ip-helper to a wintel dhcp server on vlan 21.

I dont want vlan 7 clients to get dhcp from vlan 21

Is this possible?

Graham

[cadet alain]

Hi,

yes it's possible.

just create a scope on this device for vlan7.

Regards.

Alain.

[grahamhyland]

Thanks - How do I do that?

conf t

int vlan 7

the only option in here is ip dchp relay

Graham

[lgijssel]

Hi Graham,

This is possible. All you need to do is create a dhcp pool which matches the vlan 7 subnet.

As long as the ip ranges are not overlapping there is no chance of messing up.

Sample:

http://www.cisco.com/en/US/docs/ios/12_0t/12_0t1/feature/guide/Easyip2.html#wp25541

regards,

Leo

[grahamhyland]

So is it neccasarry to give the vlan an ip add ?

[Latchum Naidu]

Hi Graham,

It is possible.

Configure DHCP on your switch like below and apply ip-helper 1.1.1.1 under the particular vlan 7.

And for the rest of the vlans remain as the ip-helper wintel dhcp server.

Configure an IP address on the router's Ethernet port, and bring up the interface. (On an existing router, you would have already done this.)

Router(config)# interface ethernet0/0
Router(config-if)#ip address 1.1.1.1 255.0.0.0
Router(config-if)# no shutdown

Create a DHCP IP address pool for the IP addresses you want to use.
Router(config)# ip dhcp pool mypool
Router(dhcp-config)# network 1.1.1.0 /8
Router(dhcp-config)#domain-name mydomain.com
Router(dhcp-config)#dns-server 1.1.1.10 1.1.1.11
Router(dhcp-config)#default-router 1.1.1.1
Router(dhcp-config)#lease 7Exit Pool Configuration Mode.
Router(dhcp-config)#exit

int vlan 7
ip-helper 1.1.1.1

Please rate the helpful posts.
Regards,
Naidu.