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DHCP Relay on EX3400

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  • 1.  DHCP Relay on EX3400

    Posted 03-14-2017 12:25

    How do you configure DHCP-Relay on the new EX3400 switches (version: 15.1X53-D55.5)?  It used to be as simple as this:

     

    set forwarding-options helpers bootp server 10.100.134.10
    set forwarding-options helpers bootp interface vlan.10
    set forwarding-options helpers bootp interface vlan.20

     

    Please help.  I am trying to configure a new switch.  A configuration example based on the above would be great.

     

    Thank you!!



  • 2.  RE: DHCP Relay on EX3400
    Best Answer

    Posted 03-14-2017 13:01

    EX3400 is using ELS-style config. Example below:

     

    jh@fw# show forwarding-options
    dhcp-relay {
        server-group {
            dhcp-server {
                1.2.3.4;
            }
        }
        active-server-group dhcp-server;
        group dhcp-server {
            interface irb.10;
            interface irb.20;
        }
    }
    
    jh@fw# show forwarding-options | display set
    set forwarding-options dhcp-relay server-group dhcp-server 1.2.3.4
    set forwarding-options dhcp-relay active-server-group dhcp-server
    set forwarding-options dhcp-relay group dhcp-server interface irb.10
    set forwarding-options dhcp-relay group dhcp-server interface irb.20
    

    #DHCPRelay
    #ex3400


  • 3.  RE: DHCP Relay on EX3400

    Posted 03-14-2017 13:35

    Thanks Jonas for the reply.  Is this the minimal required configuration for a simple DHCP Helper?  JTAC suggested this:

     

    set forwarding-options dhcp-relay forward-snooped-clients all-interfaces

    set forwarding-options dhcp-relay overrides allow-snooped-clients

    set forwarding-options dhcp-relay overrides delete-binding-on-renegotiation

    set forwarding-options dhcp-relay overrides layer2-unicast-replies

    set forwarding-options dhcp-relay overrides trust-option-82

    set forwarding-options dhcp-relay server-group DHCP-SERVER 10.12.254.16

    set forwarding-options dhcp-relay group DATA active-server-group DHCP-SERVER

    set forwarding-options dhcp-relay group DATA interface irb.1611

    set forwarding-options dhcp-relay group DATA interface irb.1638

    set forwarding-options dhcp-relay group DATA interface irb.2376

     

    I think what JTAC suggested is over-kill for what I am trying to accomplish.

     

    Thanks!!



  • 4.  RE: DHCP Relay on EX3400

    Posted 03-14-2017 13:49

    Yes, this is the minimum configuration as per this tech doc: https://www.juniper.net/documentation/en_US/junos/topics/example/dhcp-subscriber-access-dhcp-relay-minimum-configuration.html

     

    Agreed that the JTAC recommended is correct but a bit overkill in many scenarios.



  • 5.  RE: DHCP Relay on EX3400

    Posted 03-14-2017 14:05

    Hello Natesinz,

     

    This is a basic DHCP relay configuration on EX3400

     

    root@jtac-QFX5100-48S-6Q-r030> show configuration forwarding-options dhcp-relay

    server-group {

    serv1 {

    192.168.100.1;

    }

    }
    active-server-group serv1;

    group client1 {

    interface irb.100;

    }

     

    root@olympic> show configuration system services

    dhcp-local-server  {

    group serv1 {

    interface interface interface

    xe-0/0/2.0;

    irb.200;

    lo0.0;

    }

    }

     

     

    Thanks and regards,

    Murugappan 

    Juniper JTAC EX-QFX Series