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DHCP replay not working on EX4300

  • 1.  DHCP replay not working on EX4300

    Posted 05-05-2021 04:02

    I m trying to configure  DHCP relay for the EX-series switches following by below topology, while using one of ex switch act as a dhcp server.  Client pc is in VLAN 10 and MGMT for dhcp server is VLAN3 192.168.3.1. EX4300 is confiigure as dhcp relay and ex 2300 configure as local dhcp server. A pc direct connect to ex2300 local dhcp server able to grab IP adress but unable to grab any IP if connect to ex4300 go tru dhcp relay.

    dhcp relay configure on ex4300
    master:0}[edit forwarding-options dhcp-relay]
    root@TEST# show
    server-group {
    dhcp-server {
    192.168.3.1; <--- my dhcp local server 
    }
    }
    active-server-group dhcp-server;
    group dhcp-server {
    interface irb.10; 
    }

    Topology:

    [Client PC] --- ge-0/0/1 [EX4300 Switch] ge0/0/0 --- ge0/0/0[DHCP Server Ex2300]



    ------------------------------
    KUEH SI SHYAN
    ------------------------------


  • 2.  RE: DHCP replay not working on EX4300

     
    Posted 05-05-2021 05:32
    Does irb.10 have a layer 3 address? Does the EX4300 have a route to 192.168.3.0/x? Does the EX2300 have a route back to the irb.10 subnet?


  • 3.  RE: DHCP replay not working on EX4300

    Posted 05-08-2021 06:17
    attach output of show dhcp relay statistics

    ------------------------------
    Anatoliy Kushner
    ------------------------------



  • 4.  RE: DHCP replay not working on EX4300

     
    Posted 05-05-2021 17:06
    I believe the active-server-group dhcp-server needs to be added under group too.

    set group dhcp-server active-server-group dhcp-server

    And with irb interfaces we need to add broadcast as well.
    set group dhcp-server broadcast


    ------------------------------
    Steve Puluka BSEET - Juniper Ambassador
    IP Architect - DQE Communications Pittsburgh, PA (Metro Ethernet & ISP)
    http://puluka.com/home
    ------------------------------



  • 5.  RE: DHCP replay not working on EX4300

    Posted 05-06-2021 14:46
    Your config looks good..
    If your 4300 has re filter you have to allow dhcp that traffic or it gets dropped.


    set firewall family inet filter RE term allow-any-from-dhcp from source-address 192.168.3.1/32
    set firewall family inet filter RE term allow-any-from-dhcp then count allow-any-from-dhcp
    set firewall family inet filter RE term allow-any-from-dhcp then syslog
    set firewall family inet filter RE term allow-any-from-dhcp then accept

    set firewall family inet filter RE term allow-any-to-dhcp from destination-address 192.168.3.1/32
    set firewall family inet filter RE term allow-any-to-dhcp then count allow-any-to-dhcp-count
    set firewall family inet filter RE term allow-any-to-dhcp then syslog
    set firewall family inet filter RE term allow-any-to-dhcp then accept


  • 6.  RE: DHCP replay not working on EX4300

    Posted 05-05-2021 16:29
    yes both switch having l3 for mgmt n data segment, and all the segement were reachable

    ------------------------------
    KUEH SI SHYAN
    ------------------------------



  • 7.  RE: DHCP replay not working on EX4300

    Posted 05-07-2021 04:09
    yes i did try before active on the group before and broadcast command was not supported.

    ------------------------------
    KUEH SI SHYAN
    ------------------------------



  • 8.  RE: DHCP replay not working on EX4300

    Posted 05-07-2021 04:09
    didnt apply any firewall filter too

    ------------------------------
    KUEH SI SHYAN
    ------------------------------



  • 9.  RE: DHCP replay not working on EX4300

     
    Posted 05-08-2021 06:08
    I guess posting pcaps from the client and server taken during the DHCP exchange would be the next step.