Description

This article provides information on how to configure an EX9214 device (running Junos OS Release 13.2R5.10) as a DHCP server to provide IP addresses to clients, when the client-facing interfaces are part of two separate VLANs, in two different DHCP pools, and the VLANs are part of a routing instance.

Symptoms

Configure routing instance type virtual-router with a DHCP local server and two separate DHCP pools, bound to two different subnets.

The default gateway for each subnet is two IRBs added to the routing instance.

Solution

Implement routing instance type virtual-router with DHCP local server and two separate DHCP pools, bound to two different subnets.

Setup:

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  1. Configure the Ethernet switching VLANs and interfaces.

    set vlans vlan_3000 vlan-id 3000
    set vlans vlan_3001 vlan-id 3001
    set interfaces ge-11/0/1 unit 0 family ethernet-switching interface-mode access vlan members vlan_3000
    set interfaces ge-11/0/2 unit 0 family ethernet-switching interface-mode access vlan members vlan_3001

  2. Configure Integrated Routing and Bridging (IRB).

    set interfaces irb unit 3000 family inet address 10.40.0.2/24
    set interfaces irb unit 3001 family inet address 10.40.1.2/24

  3. Link the Layer 2 VLAN to the logical Layer 3 IRB interface.

    set vlans vlan_3000 l3-interface irb.3000
    set vlans vlan_3001 l3-interface irb.3001

  4. Create a routing-instance type virtual-router.

    set routing-instances DHCP-VR instance-type virtual-router

  5. Assign the IRB to the routing-instance type virtual-router.

    set routing-instances DHCP-VR interface IRB.3000
    set routing-instances DHCP-VR interface IRB.3001

  6. Configure the DHCP server and DHCP pools/ranges.

    set routing-instances DHCP-VR system services dhcp-local-server group group-1 interface irb.3000
    set routing-instances DHCP-VR system services dhcp-local-server group group-1 interface irb.3001
    set routing-instances DHCP-VR access address-assignment pool dhcp0-vr-dhcp family inet network 10.40.0.0/24
    set routing-instances DHCP-VR access address-assignment pool dhcp0-vr-dhcp family inet range range-0 low 10.40.0.50
    set routing-instances DHCP-VR access address-assignment pool dhcp0-vr-dhcp family inet range range-0 high 10.40.0.250
    set routing-instances DHCP-VR access address-assignment pool dhcp0-vr-dhcp family inet dhcp-attributes router 10.40.0.2
    set routing-instances DHCP-VR access address-assignment pool dhcp1-vr-dhcp family inet network 10.40.1.0/24
    set routing-instances DHCP-VR access address-assignment pool dhcp1-vr-dhcp family inet range range-1 low 10.40.1.50
    set routing-instances DHCP-VR access address-assignment pool dhcp1-vr-dhcp family inet range range-1 high 10.40.1.250
    set routing-instances DHCP-VR access address-assignment pool dhcp1-vr-dhcp family inet dhcp-attributes router 10.40.1.2

  7. For verification, run the show dhcp server statistics routing-instance DHCP-VR command.

    franky@test-EX9214-r001-re0> ...tics routing-instance DHCP-VR
    Packets dropped:
    Total 0
    Messages received:
    BOOTREQUEST 151
    DHCPDECLINE 0
    DHCPDISCOVER 9
    DHCPINFORM 32
    DHCPRELEASE 3
    DHCPREQUEST 107
    Messages sent:
    BOOTREPLY 116
    DHCPOFFER 9
    DHCPACK 107
    DHCPNAK 0
    DHCPFORCERENEW 0

    The DHCP process should show as:

    franky@test-EX9214-r001-re0> show system processes extensive | grep dhcp
    97190 root 1 96 0 79740K 13540K select 0:06 0.00% jdhcpd