Specifying The Source Address And Gateway Address In Dhcp Requests; Configuring The Dhcp Relay Agent Security Features; Enabling The Dhcp Relay Agent To Record Relay Entries - HPE FlexNetwork MSR Series Comware 7 Layer 3 - Ip Services Configuration Manuals

Follow these guidelines when you specify a DHCP server address on a relay agent:
•
The IP address of any specified DHCP server must not reside on the same subnet as the IP
address of the relay interface. Otherwise, the clients might fail to obtain IP addresses.
•
You can specify a maximum of eight DHCP servers.
To specify a DHCP server address on a relay agent:
Step
1. Enter system view.
2. Enter interface view.
3. Specify a DHCP server
address on the relay agent.
Specifying the source address and gateway
address in DHCP requests
Perform this task to configure the relay agent to pad the source address and gateway address in
DHCP requests with the public IP address of the loopback interface. This configuration is required for
successful packet forwarding when the DHCP server is in the public network and the DHCP clients
are in a private network.
To use this feature, you must configure the sub-option 72 in Option 82 to carry the index of the
interface that processes the DHCP request. When receiving a DHCP response, the relay agent
forwards the response according to the interface index in sub-option 72.
To specify the source address and gateway address in DHCP requests:
Step
1. Enter system view.
2. Enter interface view.
3. Specify an IP address as the
source address and gateway
address in DHCP requests.
Configuring the DHCP relay agent security
features

Enabling the DHCP relay agent to record relay entries

Perform this task to enable the DHCP relay agent to automatically record clients' IP-to-MAC bindings
(relay entries) after they obtain IP addresses through DHCP.
Some security features use the relay entries to check incoming packets and block packets that do
not match any entry. In this way, illegal hosts are not able to access external networks through the
relay agent. Examples of the security features are ARP address check, authorized ARP, and IP
source guard.
Command
system-view
interface interface-type
interface-number
dhcp relay server-address
ip-address
Command
system-view
interface interface-type
interface-number
dhcp relay source-address
ip-address
75
Remarks
N/A
N/A
By default, no DHCP server
address is specified on the relay
agent.
Remarks
N/A
N/A
By default, the IP address of the
interface is used as the source
address and gateway address in
DHCP requests.