IP Routing Features 
Configuring DHCP Relay 
Minimum Requirements for DHCP Relay Operation 
For the DHCP Relay agent to work, the following steps must be completed: 
1.  DHCP Relay is enabled on the routing switch (the default setting) 
2.  A DHCP server is servicing the routing switch 
3.  IP Routing is enabled on the routing switch 
4.  There is a route from the DHCP server to the routing switch and back 
5.  An IP Helper address is configured on the routing switch, set to the IP 
address of the DHCP server on the VLAN connected to the DHCP Client. 
Enabling DHCP Relay 
The factory-default configuration enables DHCP. However, if DHCP has been 
disabled, you can re-enable it at the Config CLI context level by entering this 
command: 
HPswitch(config)# dhcp-relay 
To disable the DHCP Relay function, enter the command: 
HPswitch(config)# no dhcp-relay 
Configuring a Helper Address 
At the VLAN configuration CLI context level, enter the commands to add the 
DHCP server’s IP address to the VLANs list. For example, to configure a helper 
address for VLAN 1, enter these commands: 
HPswitch(conf)# vlan 1 
HPswitch(vlan-1)# ip helper-address < ip-addr > 
To remove the DHCP server helper address, enter this command: 
HPswitch(vlan-1)# no ip helper-address < ip-addr > 
You can configure up to 256 IP helper addresses in the switch. 
Note  For the Series 5300xl switches only, software release E.08.07 or greater is 
required to support 256 IP helper addresses. Earlier releases support only 128 
IP helper addresses. All other switch models covered by this guide allow 256 
IP helper addresses, regardless of the software version running on the switch. 
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