Netgear XCM8810 - 8800 SERIES 10-SLOT CHASSIS SWITCH ユーザーズマニュアル

enable ipforwarding

DHCP/BOOTP Relay

After IP unicast routing has been configured, you can configure the switch to forward 
Dynamic Host Configuration Protocol (DHCP) or BOOTP requests coming from clients on 
subnets being serviced by the switch and going to hosts on different subnets. This feature 
can be used in various applications, including DHCP services between Windows NT servers 
and clients running Windows 95. To configure the relay function:

Configure VLANs and IP unicast routing.

Enable the DHCP or BOOTP relay function, using the following command:

enable bootprelay {{vlan} [<vlan_name>] | {{vr} <vr_name>} | all [{vr} <vr_name>]}

Configure the addresses to which DHCP or BOOTP requests should be directed, using the 
following command:

configure bootprelay add <ip_address> {vr <vrid>}

To delete an entry, use the following command:

configure bootprelay delete [<ip_address> | all] {vr <vrid>}

To disable BOOTP relay on one or more VLANs, use the following command:

disable bootprelay {{vlan} [<vlan_name>] | {{vr} <vr_name>} | all [{vr} 

<vr_name>]}

To view the BOOTP relay enable/disable configuration, use the following command:

show bootprelay configuration {{vlan} <vlan_name> | {vr} <vr_name>}

When VRRP and BOOTP/DHCP relay are both enabled on the 

switch, the relayed BOOTP agent IP address is the actual switch IP 
address, not the virtual IP address.

Configuring the DHCP Relay Agent Option (Option 82) at 

Layer 3

After configuring and enabling the DHCP/BOOTP relay feature, you can enable the DHCP 
relay agent option feature. This feature inserts a piece of information, called option 82, into 
any DHCP request packet that is to be relayed by the switch. Similarly, if a DHCP reply 
received by the switch contains a valid relay agent option, the option is stripped from the 
packet before it is relayed to the client.

When DHCP option 82 is enabled, two types of packets need to be handled:

DHCP Request: When the switch (relay agent) receives a DHCP request, option 82 is 

added at the end of the packet. If the option has already been enabled, then the action