Cat 6509 - Multiple VLAN DHCP relay .Switch running native IOS

[ra_comms]

I have a problem to set dhcp relay with Catalyst 6509 switch with sup and msfc cards and running native ios ver 12.1(8a)E4.

I have specified "IP helper address" in the vlan interface where the dhcp client is connected it doesnt help.

"no ip directed-broadcast" doesnt appear in the interface config while doing a "show run" or "sh start" commands.

dhcp server functions perfectly when dhcp clients moved to the same vlan subnet.Switch routing works with static address.

I tried to enable "directed-broadcast" with access-list in the vlan interface and enabling "ip forward protocol udp ports 67 and 68" and "ip dhcp smart-relay" in global config mode still it doesnt help.

I tried the same interface config with a cisco 2611 router and placing the dhcp server in one interface and dhcp client in other interface it works.The "no ip directed-broadcast" parameter appears in the router "sh run" or "sh start".

Anybody has got an idea and advice how to get dhcp relay functioning in our switches

[ehyman]

I would verify that you entered the "no shut" command on the vlan interface and that the helper address is pointing to the dhcp server.

[adignan]

e-mail me your configs at adignan@n2nsolutions.com

[cgarofalo]

I Had the same problem with my Catalyst 6509. I didn't find a solution for it.

I resolved this problem to assign the IP addresses in the DHCP Server with the MAC addresses of the clients.

So the switch with this configuration work properly

Regards, Carmelo

[zhengliu]

Sounds like a ios bug if your configuration is right and it can work on cisco 26xx router.

Cisco engineers suggest to use catalyst version software of 6000 family.

[rfroom]

Is IP helper-address pointing to a unicast IP address or broadcast address? check out the troubleshooting described in the following document:

http://www.cisco.com/warp/public/473/100.html

Taking a sniffer trace should help us narrow down the problem.