Wireless Access

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Access network design for branch, remote, outdoor, and campus locations with HPE Aruba Networking access points and mobility controllers.
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ip-helper

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  • 1.  ip-helper

    Posted Oct 26, 2015 08:11 PM

     

    Hi.
    We have 4 Corridors
    Corridor 400 stands alone on one side of the building.
    We have an S2500 in the 400 Corridor that acts as our Primary Router.
     
    We also have 2- S1500 in the 400 Corridor used for the AP's connectivity. That switch's gateway is the 400 Corridor S2500.
     
    On the other side of the building we have 3 floors.
     
    We have an S1500 in the basement for our AP's, an S1500 on the 3rd floor for the AP's and an S1500 on the 2nd floor for the AP's.
     
    On the 2nd floor we also have another S2500 which acts as a secondary router, since 3/4 of the traffic comes from that side.
     
    My question is, do i need to put the ip-helper on all vlan interfaces of each switch, or just on the vlan interfaces of both S2500's?
     
    Thank you.

     



  • 2.  RE: ip-helper

    EMPLOYEE
    Posted Oct 26, 2015 09:06 PM

    Question:  What do you want to do?

     



  • 3.  RE: ip-helper

    Posted Oct 26, 2015 09:23 PM

    Hi
    I need to know if I need to put the ip - helper on each vlan interface on
    every switch. I currently have it on my primary router.

    Thank you for your quick response.




  • 4.  RE: ip-helper

    EMPLOYEE
    Posted Oct 26, 2015 09:25 PM
    In general, you would only put a helper address on the layer3 interface of a vlan.


  • 5.  RE: ip-helper

    Posted Oct 26, 2015 09:33 PM

    I see.
    I did put it on every vlan interface on one switch, before I reached out
    for guidance. Will that create a problem? Would you happen to know the
    command to remove the dhcp relay setting?
    Thank you very much for your help on this.




  • 6.  RE: ip-helper
    Best Answer

    EMPLOYEE
    Posted Oct 27, 2015 05:28 AM

    You would generally just put it on the vlan interface for the core switch/router.  If you add to every switch you could end up with multiple addresses being assigned to the same device and then wasted dhcp addresses, cause only one will be taken by the device.



  • 7.  RE: ip-helper

    Posted Dec 13, 2015 04:57 PM

    Hi.

    Thank you for yoru continued help with my problem.

    I do have DHCP relay on the s2500 core router\switch.

    Originally, someone setup our current HP switches, using the Aruba S2500 as the router. There is one s1500 that is directly connected to the S2500, via a port channel, and that works fine without the dhcp relay on it.

    When I go to upgrade other HP switches to the s1500,  the s1500 doesn't work until I put dhcp relay on it. But dhcp relay shouldn't be configured on each switch?

     



  • 8.  RE: ip-helper

    Posted Dec 20, 2015 02:22 PM

    it depends on if you use l3 interfaces on those switch or just extend the l2 network. if they have seperate l3 interfaces / networks you need dhcp relay, if you just extend the l2 network the dhcp request ends up at the l3 interface of the core switch.



  • 9.  RE: ip-helper

    EMPLOYEE
    Posted Dec 13, 2015 04:40 PM
    Whichever VLAN interface is the client's default gateway.

    Sent from Nine