DHCP option 82

Owned by Jean-luc KRIKER
Last updated: Apr 03, 2020
3 min read



DHCP relay option
option
Netbox@RL104-SRX1500-B# set routing-instances vrouter1 forwarding-options dhcp-relay relay-option ?
Possible completions:
  <[Enter]>            Execute this command
+ apply-groups         Groups from which to inherit configuration data
+ apply-groups-except  Don't inherit configuration data from these groups
> option-60            Add option 60 processing
> option-77            Add option 77 processing
> option-order         Options precedence order
  |                    Pipe through a command
[edit]
DHCP relay option 82

https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/dhcp-subscriber-access-dhcp-relay-using-option-82-overview.html

https://www.juniper.net/documentation/en_US/junos/topics/reference/configuration-statement/relay-option-82-edit-forwarding-options.html

option 82
Netbox@RL104-SRX1500-B# set routing-instances vrouter1 forwarding-options dhcp-relay relay-option-82 circuit-id ?
Possible completions:
  <[Enter]>            Execute this command
+ apply-groups         Groups from which to inherit configuration data
+ apply-groups-except  Don't inherit configuration data from these groups
  include-irb-and-l2   Include IRB and L2 interface name
  keep-incoming-circuit-id  Keep incoming circuit identifier
  no-vlan-interface-name  Not include vlan or interface name
> prefix               Add prefix to circuit/interface-id or remote-id
  use-interface-description  Use interface description instead of circuit identifier
  use-vlan-id          Use VLAN id instead of name
  user-defined         Include user defined string
  |                    Pipe through a command
[edit]
DHCP client leasingthe Client will renew the lease 1/2 of the lease time ( eg: if lease time = 10mins, after 5min the client request an IP@)
MX config

To take effect clear the binding on the Relay and DHCP server:

clear dhcp relay binding 10.10.3.2

clear dhcp server binding 10.10.3.2

MX DHCP relay
jcluser@vMX2> show configuration forwarding-options
dhcp-relay {
    overrides {
        proxy-mode;
    }
    relay-option-82 {
        circuit-id {
            use-interface-description logical;
        }
        remote-id;
    }
    server-group {
        relaygrp {
            10.0.0.1;
        }
    }
    active-server-group relaygrp;
    group toclient {
        interface ge-0/0/3.0;
    }
}

jcluser@vMX2> show configuration forwarding-options | display set
set forwarding-options dhcp-relay overrides proxy-mode
set forwarding-options dhcp-relay relay-option-82 circuit-id use-interface-description logical
set forwarding-options dhcp-relay relay-option-82 remote-id
set forwarding-options dhcp-relay server-group relaygrp 10.0.0.1
set forwarding-options dhcp-relay active-server-group relaygrp
set forwarding-options dhcp-relay group toclient interface ge-0/0/3.0