Creating a DHCPv4 Server Group

Procedure

1. Run system-view

   The system view is displayed.

2. Run dhcp-server group group-name

   A DHCPv4 server group is created and the DHCPv4 server group view is displayed.

3. Run dhcp-server ip-address [ vpn-instance vpn-instance ] [ weight weight-value ]

   A DHCPv4 server is configured.

   A DHCPv4 server group can contain one master DHCPv4 server and a maximum of seven backup DHCPv4 servers.

4. (Optional) Run dhcp-server algorithm { loading-share | master-backup | polling [ check-loose ] }

   The algorithm for selecting DHCPv4 servers is configured.

   This command takes effect only when a DHCPv6 server group contains two DHCPv6 servers. The servers can work in load balancing, polling, or master/backup mode.

   • Load balancing: The NetEngine 8000 F distributes traffic based on the weights of DHCPv4 servers.
   • Master/backup: The server configured earlier is the master server, and the other is the backup server.

   • Polling: The NetEngine 8000 F sends a request message to both of the two servers and selects the server that receives the request message earlier. All the subsequent messages, except DHCP Discover and DHCP Request messages, are sent only to the selected server.

5. (Optional) Run release-agent

   The DHCPv4 release agent function is configured.

   When a user wants to go offline and the DHCPv4 release agent function is enabled, the NetEngine 8000 F, instead of the user, sends DHCPv4 Release messages to DHCPv4 servers.

6. (Optional) Run dhcp rebind forward-mode all

   The NetEngine 8000 F is configured to forward DHCP Rebind messages to all DHCPv4 servers in the DHCPv4 server group.

7. (Optional) Run dhcp-server giaddr { interface interface-type interface-number | ip-address [ vpn-instance vpn-instance ] } [ forward-rui-slave ]

   The GiAddr address of the DHCP messages sent from the DHCPv4 server group is configured.

8. Run quit

   Return to the system view.

9. (Optional) Run access user-ip-address trust dhcp-server user-type ppp

   The NetEngine 8000 F is enabled to perform loose check on the IP addresses assigned by DHCPv4 servers from a remote address pool for PPP and L2TP users.

10. (Optional) Run dhcp-server [ ip-address [ vpn-instance vpn-instance ] ] { dead-count dead-count | timeout timeout-value | dead-time dead-time }^*

    The maximum number of times no response message is sent by a DHCPv4 server as a response to a request message is configured.

    This command is used to resolve the problem of repeated status switching of a DHCPv4 server. After this command is configured, a DHCPv4 server automatically goes down after the number of times no reply message is sent by a DHCPv4 server as a response to a request message exceeds the specified threshold.

11. (Optional) Run dhcp-server [ ip-address [ vpn-instance vpn-instance ] ] nak-count nak-count

    The maximum number of consecutive DHCP Nak messages that can be received from a DHCPv4 server is configured. A DHCPv4 server automatically goes down if the number of consecutive DHCP Nak messages received from the DHCPv4 server exceeds the specified threshold.

12. (Optional) Run dhcp option-82 agent-remote-id strip

    The router is enabled to remove the remote-id information from the Option 82 attribute of DHCP messages.

13. (Optional) Configure CAR for whitelisted DHCPv4 sessions.
    1. (Optional) Run the undo whitelist session-car dhcp-server disable command to enable CAR for whitelisted DHCPv4 sessions.
    2. Run the whitelist session-car dhcp-server { cir cir-value | cbs cbs-value | pir pir-value | pbs pbs-value } * command to configure the bandwidth parameters of CAR for whitelisted DHCPv4 sessions.
14. Run commit

    The configuration is committed.