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Setup DHCP Helper On HP E-Series Procurve

If you have created VLAN`s on you HP e-series switch/router then you may want DHCP from your DHCP server to be able to service devices that are connected to your VLAN`s, by default the DHCP broadcast will not pass through the router/switch without a helper address setup on the VLANs.

First check you have setup your vlans correctly on your access layer.

On the distribution layer ( your core switch / router ) you will also need to setup the vlans to match your access layer, however on each vlan you will need to setup the ip-helper address. This means that when a device sends out a DHCP request it does so on 255.255.255.255, as the e series is a layer 3 switch/router we can set it up as a DHCP relay.To do so do the following. ( in my example my core is called “router” ).

Go to the vlan you want to setup the ip helper address on.

Router (vlan10)#

Now enter the ip address and subnet of the DHCP server.

ip helper-address  10.5.5.1/24

Finally we need to enable IP Routing for this to work. Use the command below.

ip routing

Now when a device on VLAN 10 sends a DHCP request out, the router will forward the request to 10.5.5.1 ( the DHCP server). If you have multiple scopes then the DCHP server will issue an address based on the IP address of the VLAN that the device that has sent the DHCP request.

Remember if you struggle with the syntax of any command, partially type the command then press tab, see see all extension add a ? to the end of the coomand