Routing

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Ask questions and share experiences about ACX Series, CTP Series, MX Series, PTX Series, SSR Series, JRR Series, and all things routing, including portfolios and protocols.

  • 1.  DHCP Relay Not Forwarding Offers

    Posted 29 days ago
    Edited by spuluka 28 days ago

    Trying to configure DHCP Relay in a routing instance on an ACX7024 (Evo)

    The ACX is forwarding the discovers to the DHCP server and offers and being returned but they are being dropped by the ACX so not reaching the end devices.

    Have been banging my head on this for hours now and can't seem to resolve. Routing instance config is below

    set routing-instances TEST forwarding-options dhcp-relay overrides allow-snooped-clients
    set routing-instances TEST forwarding-options dhcp-relay overrides no-bind-on-request
    set routing-instances TEST forwarding-options dhcp-relay overrides delete-binding-on-renegotiation
    set routing-instances TEST forwarding-options dhcp-relay server-group TEST 100.127.0.64
    set routing-instances TEST forwarding-options dhcp-relay active-server-group TEST
    set routing-instances TEST forwarding-options dhcp-relay group TEST_INTERFACES interface et-0/0/4.2890
    set routing-instances TEST forwarding-options dhcp-relay group TEST_INTERFACES interface irb.2010

    Stats

    Packets dropped:
        Total                      951
        No binding found           951
     
    Messages received:
        BOOTREQUEST                957
        DHCPDECLINE                0
        DHCPDISCOVER               957
        DHCPINFORM                 0
        DHCPRELEASE                0
        DHCPREQUEST                0
        DHCPLEASEACTIVE            0
        DHCPLEASEUNASSIGNED        0
        DHCPLEASEUNKNOWN           0
        DHCPLEASEQUERYDONE         0
        DHCPACTIVELEASEQUERY       0
     
    Messages sent:
        BOOTREPLY                  0
        DHCPOFFER                  0
        DHCPACK                    0
        DHCPNAK                    0
        DHCPFORCERENEW             0
        DHCPLEASEQUERY             0
        DHCPBULKLEASEQUERY         0
        DHCPLEASEACTIVE            0
        DHCPLEASEUNASSINGED        0
        DHCPLEASEUNKNOWN           0
        DHCPLEASEQUERYDONE         0
        DHCPACTIVELEASEQUERY       0

    Last entry in logs

    Feb 15 20:59:00.948438000 [MSTR][DEBUG][default:CIP_TEST][RLY][INET][et-0/0/4.2890] jdhcpd_process_forward_only_or_drop: Returning ... forward-only flags not set (flags=0, rc_flags 8a0040d) for routing context 52
    Feb 15 20:59:00.948455000 [MSTR][NOTE] [default:CIP_TEST][RLY][INET][et-0/0/4.2890] jdhcpd_packet_handle: BOOTPREPLY could not find client table entry
    Have tried with forward-only but makes no difference. Any help appreciated!
    Thanka





  • 2.  RE: DHCP Relay Not Forwarding Offers

    Posted 28 days ago
    Edited by sidders54 28 days ago

    I believe I have found the cause. DHCP offers don't include option 82 so are dropped. 3 solutions are offered. Any idea how to do solution 2 on Evo?

    • Solution 1: Upgrade the DHCP Server to Junos OS version that fully supports Option 82.

    • Solution 2: Change the DHCP Relay to a "stateful" mode (that is, DHCP Relay "binding" mode).

    • Solution 3: Move the DHCP Relay to a MX or to a non-ELS EX/QFX switch, so to enable the Legacy 'helper bootp' mode.


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    Original Message


  • 3.  RE: DHCP Relay Not Forwarding Offers

    Posted 22 days ago

    Anyone got any suggestions please?



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    Nick Harrington
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    Original Message


  • 4.  RE: DHCP Relay Not Forwarding Offers

    Posted 22 days ago

    I'm wondering why there are two interfaces listed in your configuration.  I assume that the irb is the layer 3 interface for the forwarding subnet and matches what the dhcp server is expecting for the reservations. 

    If the et interface is layer 2 this should be removed.

    Also be sure the interfaces themselves are correctly assigned to the TEST routing instance



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