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ArubaOS-CX DHCP-Server Initial Setup

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  • 1.  ArubaOS-CX DHCP-Server Initial Setup

    EMPLOYEE
    Posted Aug 25, 2020 05:24 PM

    I'm having some trouble getting DHCP-Server up and running on an OS-CX switch, a 6405. Running OS 10.05.0001.

     

    I lend my experience from AOS/Comware, where a dhcp pool is defined then attached to a VLAN/Interface.

     

    In OS-CX, that construct seems to have moved to VRF (at least what I've learned from the docs).

     

    I've created a dhcp-server for the default vrf (where a few VLANs live that I want to offer DHCP), created a pool with appropriate options, but clients are not getting addresses in said VLAN.

     

    Here are some config snippets:

     

     

    dhcp-server vrf default
pool vlan965
range 10.207.5.201 10.207.5.220 prefix-len 24
default-router 10.207.5.1
lease 00:10:00
exit
authoritative
enable

interface vlan 965
ip address 10.207.5.1/24

interface 1/5/2
no shutdown
no routing
vlan access 965

     

     

    There is a ToR switch downstream, along with a host and VM. The VM can communicate with a static IP, but a second NIC will not get a DHCP offer.

     

    I feel like I'm missing that "attach dhcp to vlan" bit like Comware/AOS.

     

    I don't want to separate these VLANs into seperate VRFs just to run DHCP on the switch. Is there another way to accomplish this? Is VRF the only way?

     

    Thanks!

     



  • 2.  RE: ArubaOS-CX DHCP-Server Initial Setup

    Posted Aug 25, 2020 08:52 PM

    Do you have any ip-helper / relay on the switch?

    CX does not support DHCP serer and relay on the same switch.



  • 3.  RE: ArubaOS-CX DHCP-Server Initial Setup

    EMPLOYEE
    Posted Aug 26, 2020 08:18 AM

    No DHCP helper/relay configured on the switch globally (entire environment is strictly statically assigned).



  • 4.  RE: ArubaOS-CX DHCP-Server Initial Setup

    EMPLOYEE
    Posted Aug 26, 2020 08:58 AM

    Could you share the output of show dhcp-server vrf default  ?



  • 5.  RE: ArubaOS-CX DHCP-Server Initial Setup

    EMPLOYEE
    Posted Aug 26, 2020 10:41 AM

    Sure, thanks!

     

    VRF Name           : default
DHCP Server        : enabled
Operational State  : operational
Authoritative Mode : true

Pool Name          : vlan965
Lease Duration     : 00:10:00

DHCP dynamic IP allocation
----------------------------
Start-IP-Address           End-IP-Address             Prefix-Length
-----------------          ---------------            -------------
10.207.5.201               10.207.5.220               24


DHCP Server options
---------------------
***************************************************
Note:DHCP Server well known option number mapping:
default-router(3), Dns-server(6), Domain-name(15),
Netbios-name-server(44), Netbios-node-type(46)
***************************************************
Option-Number       Option-Type          Option-Value
--------------      ------------         -------------
 3                  ip                   10.207.5.1


DHCP Server static IP allocation
----------------------------------
DHCP Server static host is not configured.


BOOTP Options
---------------
Boot-File-Name            TFTP-Server-Name               TFTP-Server-Address
---------------           -----------------              ---------------------
*                         *                              *

     



  • 6.  RE: ArubaOS-CX DHCP-Server Initial Setup

    EMPLOYEE
    Posted Aug 26, 2020 10:52 AM

    Please putting these 2 lines:

    range 10.207.5.201 10.207.5.220

    range 10.207.5.201 10.207.5.254 prefix-len 24

     



  • 7.  RE: ArubaOS-CX DHCP-Server Initial Setup
    Best Answer

    EMPLOYEE
    Posted Aug 26, 2020 04:58 PM

    OK, here is the latest config:

     

     

    VRF Name           : default
DHCP Server        : enabled
Operational State  : operational
Authoritative Mode : true

Pool Name          : vlan965
Lease Duration     : 00:10:00

DHCP dynamic IP allocation
----------------------------
Start-IP-Address           End-IP-Address             Prefix-Length
-----------------          ---------------            -------------
10.207.5.201               10.207.5.251               24
10.207.5.201               10.207.5.220               *


DHCP Server options
---------------------
***************************************************
Note:DHCP Server well known option number mapping:
default-router(3), Dns-server(6), Domain-name(15),
Netbios-name-server(44), Netbios-node-type(46)
***************************************************
Option-Number       Option-Type          Option-Value
--------------      ------------         -------------
 3                  ip                   10.207.5.1


DHCP Server static IP allocation
----------------------------------
DHCP Server static host is not configured.


BOOTP Options
---------------
Boot-File-Name            TFTP-Server-Name               TFTP-Server-Address
---------------           -----------------              ---------------------
*                         *                              *

     

     

     

    I also *just* realized this switch has an ACL applied to this VLAN.

     

    I added a "permit udp any any eq 67" ACE and thought I was on my way.

     

    However it still wasn't working, even though I was getting hits on the ACE. Turns out, I forgot to enable the dhcp-server after changing the pool. duuuuh

     

    *Now* its working! Thanks to all for assistance!

     

    Moral of the story, sometimes we're our own worst enemies