Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

DHCP Request over VLANs

I have 3 subnets:

10.0.4.0/22

10.0.8.0/22

10.0.32.0/22

10.0.4.0 is the admin subnet and running on VLAN1.

10.0.8.0 is the DHCP subnet and also running on VLAN1. In addition, the DHCP server (10.0.8.2) is located on this subnet.

10.0.32.0/22 is a new subnet that will be running on VLAN32.

I have a 6509 at the core with all the routing being done by a 7206. I also have a static route configured on the 6509MSFC for the 10.0.8.2 to point to the 7206 ethernet interface. I can configure static IP on the VLAN32 network and can ping the DHCP server. But when I try to get a DHCP address I am unable to, does anyone have any ideas?

7 REPLIES
Community Member

Re: DHCP Request over VLANs

use "IP HELPER 10.0.8.2" on the new ethernet interface for the 7206. That is assuming that the 7206 is directly connected to the new ethernet segment. Otherwise, put this statement on the MSFC's VLAN32 interface.

Question: If all the routing is done on a 7206, how are you using the MSFC?

Mick.

Community Member

Re: DHCP Request over VLANs

I forgot to tell that I have the ip helper-address on the ethernet interface on the 7206.

The 6509 is not being utilized the way it should. Creating this VLAN32 is the 1st step to correct that. But mainly the 6509 is being used like a L2 switch.

Community Member

Re: DHCP Request over VLANs

if you are not using layer3 on the 6509, you could add the ip-helper statement on the vlan interface on the 7206 router.

Silver

Re: DHCP Request over VLANs

Not trying to go off subject but...

If you havent already, you should configure MLS (Multi Layer Switching) on your 7206 and 6500.

This way, your 6500 can act more like a Layer 3 switch. The 7206 will be the brains, and the 6500 the brawn.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sft_6_1/configgd/mls_all.htm

Regards,

Brad H.

Community Member

Re: DHCP Request over VLANs

I agree with Brad. You have a great switch, I think you should use it as a layer3 switch.

Community Member

Re: DHCP Request over VLANs

For the VLAN 32 to contact the DHCP server in the other subnet, you need to configure ip helper address on the VLAN interface.

Try the command on the Interface VLAN 32

ip helper-address 10.0.8.2

Community Member

Re: DHCP Request over VLANs

If you had config ip helper-address correctly.

Pls check your DHCP server's config.You need create a separate scope for vlan 32.

207
Views
0
Helpful
7
Replies
CreatePlease to create content