KB.15.15

Example 127 Assigning a gateway to an interface and then displaying the information

HP Switch(vlan-22)ip bootp-gateway 12.16.18.33

HP Switch(vlan-22)# exit

HP Switch(config)# show dhcp-relay bootp-gateway vlan 22

BOOTP Gateway Entries

VLAN BOOTP Gateway

-------------------- ---------------

VLAN 22 12.16.18.33

Operating notes

• If the configured BOOTP gateway address becomes invalid, the DHCP relay agent returns to

the default behavior (assigning the lowest-numbered IP address.)

• If you try to configure an IP address that is not assigned to that interface, the configuration

fails and the previously configured address (if there is one) or the default address is used.

Configuring an IP helper address

To add the IP address of a DHCP server for a specified VLAN on a routing switch, enter the ip

helper-address command at the VLAN configuration level as in the following example:

HP Switch(config)# vlan 1

HP Switch(vlan-1)# ip helper-address ip-addr

To remove the DHCP server helper address, enter the no form of the command:

HP Switch(vlan-1)# no ip helper-address ip-addr

Operating notes

• You can configure up to 4000 IP helper addresses on a routing switch. The helper addresses

are shared between the DHCP relay agent and UDP forwarder feature.

• A maximum of sixteen IP helper addresses is supported in each VLAN.

Disabling the hop count in DHCP requests

For more information, see “Hop count in DHCP requests” (page 237).

To disable the default behavior of a DHCP relay agent so that the hop count in a DHCP client

request is not increased by one at each hop when it is forwarded to a DHCP server, enter the no

dhcp-relay hop-count-increment command at the global configuration level:

HP Switch(config)# no dhcp-relay hop-count-increment

To reset the default function, which increases the hop count in each DHCP request forwarded to

a DHCP server, enter the following command:

HP Switch(config)# dhcp-relay hop-count-increment

230 Dynamic Host Configuration Protocol