ExtremeSwitching (EXOS)

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DHCP Standard Practise

  • 1.  DHCP Standard Practise

    Posted 01-18-2017 11:27
    I have a question regarding DHCP.

    Whats the standard practise for implementing DHCP helpers.

    Our current setup, we use UDP profile on all our vlans on our core switches that require dhcp services. this is an inherited design before my time.

    would it be more beneficial to go down the bootprelay route?

    are there any other options? pros and cons for each?

    Many Thanks
    Ian


  • 2.  RE: DHCP Standard Practise

    Posted 01-18-2017 11:36
    In early days UDP helper was the only method to be able to distinguish between vlans and DHCP servers.
    Nowadays you can enable bootprelay per vlan so you can use bootprelay without enabling it for all vlans. Still I think if you need different DHCP servers for different vlans UDP profile is the only config possible.


  • 3.  RE: DHCP Standard Practise

    Posted 01-18-2017 11:41
    We use 2 DHCP servers for all our vlans, I assume you can specify more than one server within the bootprelay config?


  • 4.  RE: DHCP Standard Practise

    Posted 01-18-2017 11:48
    Ian, it depend what you need 🙂.

    Oscar, I think you can use bootprelay with more DHCP servers, with additional config on server: agent.circuit-id, agent.remote-id, class, allow members of ... and so on.
    It will respond only to configured "class members".

    --
    Jarek


  • 5.  RE: DHCP Standard Practise

    Posted 01-18-2017 11:52
    Hi,

    the scenario is, we have two DHCP servers and I would like all DHCP requests for 20 VLANs to go to these servers.

    is it a case of;

    configure bootprelay add "DHCP Server IP 1"
    configure bootprelay add "DHCP Server IP 2"

    configure bootprelay vlan "vlan 1"
    configure bootprelay vlan "vlan 2"

    and so on.


  • 6.  RE: DHCP Standard Practise

    Posted 01-18-2017 12:05
    Simpler:

    1) confgure bootprelay servers

    configure bootprelay add 1.1.1.1 vr VR-Default
    configure bootprelay add 2.2.2.2 vr VR-Default

    2) enable bootprelay

    enable bootprelay - "Enables the BOOTP Relay function on all VLANs"

    "If DHCP/BOOTP Relay is enabled on a per VLAN basis, make sure it is enabled on both theclient-side and server-side VLANs."

    --
    Jarek



  • 7.  RE: DHCP Standard Practise

    Posted 01-18-2017 12:11
    I was going to say, not every vlan is DHCP serviced so would i stick with my example?


  • 8.  RE: DHCP Standard Practise

    Posted 01-18-2017 12:12
    disable bootprelay vlan XXX

    --
    Jarek



  • 9.  RE: DHCP Standard Practise

    Posted 05-07-2018 13:50
    I know this is an old post, but would this configuration still be the same when working with dhcp servers in a load balancing configuration (windows server 2016)? List both servers? Does it matter which one is first?


  • 10.  RE: DHCP Standard Practise

    Posted 01-18-2017 11:41
    For example rel. notes 15.6 says that the maximum number of BOOTP or DHCP servers per virtual router is 4

    --
    Jarek