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DHCP over wireless bridge

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  • 1.  DHCP over wireless bridge

    Posted Apr 24, 2013 01:20 PM

    I'm currently having a problem over several applications that has the same root cause. Clients accessing the Aruba network via a wireless bridge cannot obtain DHCP addresses. I have three distinct use cases that I'm seeing this issue. The first is VMWare Fusion, when you put the guest into bridge mode for networking. The second issue is a few old machines that do not have wireless cards. We used a Linksys WET54G to connect these machines. Lastly we have some specialized equipment that uses a wireless bridge to connect to the network. In all of these cases if I assign a static address to the client, things work fine. This did not seem to be an issue until I upgraded our controllers to 6.x from 5.x. Is there something that has changed behavior? This seems like a setting that I'm just missing and need to turn on or off. Thanks for your help!



  • 2.  RE: DHCP over wireless bridge

    EMPLOYEE
    Posted Apr 24, 2013 01:34 PM

    What wireless bridge is this?  How it is configured and how does it connect to the network?

     



  • 3.  RE: DHCP over wireless bridge

    Posted Mar 10, 2014 02:28 PM

    This issue has cropped up again.  It was resolved last time when I upgraded firmware to 6.1.3.7 from 6.1.3.4.  After updating to 6.3.1.2, this has happened again.  Any insight into what might have caused this?



  • 4.  RE: DHCP over wireless bridge
    Best Answer

    EMPLOYEE
    Posted Mar 10, 2014 04:39 PM

    Sounds like you need to disable broadcast filter arp, or "Convert Broadcast ARP requests to unicast"  search 

     

    http://www.arubanetworks.com/techdocs/ArubaOS_63_Web_Help/Web_Help_Index.htm#ArubaFrameStyles/VirtualAPs/Configuring_a_Virtual_AP.htm

     

    "

    Starting with ArubaOS 6.1.3.2, the Convert Broadcast ARP requests to unicast  setting includes the additional functionality of broadcast-filter all parameter, where DHCP response frames are sent as unicast to the corresponding client. This can impact DHCP discover/requested packets for clients behind a wireless bridge and virtual clients on VMware devices. Disable this option to resolve this issue and allow clients behind a wireless bridge or VMware devices to receive an IP address.

    Default: Enabled"



  • 5.  RE: DHCP over wireless bridge

    Posted Mar 10, 2014 05:18 PM

    I knew this had to be something silly that I was just flat out missing.  Thanks so much for the help!!!



  • 6.  RE: DHCP over wireless bridge

    Posted May 02, 2016 11:28 PM

    I have an Aruba620 with 2 x AP205 & 2 x AP105 units connected and running ArubaOS 6.4.4.1.

     

    I'm having this same problem.

     

    I have confirmed that under:

    Configuration -> AP Configuration -> default group -> Wireless LAN -> Virtual AP -> (profile):

     

    Basic tab:

        Drop Broadcast and Unknown Multicast - OFF

        Convert Broadcast ARP requests to unicast - OFF

     

    In the AAA Profile, I have also confirmed that "Enforce DHCP" is set to OFF.

     

    I'm connecting an ethernet device to a network via a bridge wifi device - and nothing behind the bridge gets any traffic.

     

    Is there anything further that may stop this?



  • 7.  RE: DHCP over wireless bridge

    EMPLOYEE
    Posted May 03, 2016 05:23 AM

    Which wireless bridge is this?

     



  • 8.  RE: DHCP over wireless bridge

    Posted May 03, 2016 08:09 PM

    The wireless module is an OEM board made by Hi-Flying - Model HF-A21-SMT.

     

    The manual is here:

    http://www.hi-flying.com/downloadsfront.do?method=picker&flag=all&id=26539c50-7273-4581-8af4-fe560266d928&fileId=c6005569-4f4d-4cc0-8783-ac1d847a39f3

     

    The unit itself gets an IP address but nothing behind the bridge does.

     

    We have been able to get this work fine using a normal consumer grade access point.



  • 9.  RE: DHCP over wireless bridge

    Posted Jun 02, 2016 01:00 PM

    I am seeing the same issue with Fusion/etc. VMs and IAPs. Is there a similar setting within InstantOS? Is it GUI or CLI only?

     

    Thanks,

    John Chapman



  • 10.  RE: DHCP over wireless bridge

    Posted Jul 27, 2017 11:18 AM

    So what is the impact of turning off Convert Broadcast ARP requests to unicast?  I understand this allows bridged devices to work (we had to do this for a 1-off config at our hospital) but should I be concerned about potential detremental impacts of allowing all of the extra broadcast traffic.

     

    As always, thanks for your time.



  • 11.  RE: DHCP over wireless bridge

    EMPLOYEE
    Posted Jul 27, 2017 12:16 PM

    Depending on how large your subnet is, turning off "Convert" might not add too much in the way of broadcasts to your environment.  You should try it and see if you have any issues.