Routing

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  • 1.  DHCP relay over routing instances

    Posted 11-17-2022 19:36
    Hi experts, I am new to Juniper and I got this project to see if I can make DHCP relay work between the routing instances. Here is my topology for my lab

    DHCP server .254 ------- vlan.0 (10.0.1.2/24 in default instance) [EX4200] vlan.2 (10.0.2.2/24 in the test instance) ------- DHCP client

    The goal is to figure out a way to do it without leaking the routes between the instances. I got it working on Cisco with option 82 suboption 151. Does Juniper have a similar way to do it? Any links are appreciated. 

    Thanks!

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    DIFAN ZHAO
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  • 2.  RE: DHCP relay over routing instances

    Posted 11-21-2022 06:51
    Hi 

    The syntax for your issue will be something like this

    set forwarding-options dhcp-relay server-group Group1 <dhcp-server-ip>
    set forwarding-options dhcp-relay active-server-group Group1
    set forwarding-options dhcp-relay server-group Group1 interface vlan.0
    set forwarding-options dhcp-relay server-group Group1 interface vlan.2

    you can edit it as per your requirement.

    https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/security-dhcp-relay-agent-minimum-configuration.html


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    ROHAN BARTHWAL
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  • 3.  RE: DHCP relay over routing instances

    Posted 11-21-2022 17:14
    Thanks Rohan! With this basic config, the switch will send the helper message with 10.0.2.2 (test VRF) as the source IP and 10.0.1.254 (default instance) as the destination. In order to make it work I will have to do route sharing between the VRF

    I am wondering if it is possible to source the helper IP out of the default instance 10.0.1.2 or vlan.0 IP on behalf of the vlan.2 subnet 10.0.2.0/24 in the test VRF? Thanks!

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    DIFAN ZHAO
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