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Aruba 8325 - IP Helper - Windows DHCP - Lots of BAD_ADDRESS

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  • 1.  Aruba 8325 - IP Helper - Windows DHCP - Lots of BAD_ADDRESS

    Posted Aug 19, 2019 10:18 AM

    Hi everyone,

     

    today I came accross a very strange phenomenon relating DHCP.

     

    We have two 8325 Switches in a VSX config. There are several VLANs configured, each with its own IP address, active-gateway and ip helper addresses for the 2 Windows Server 2016 DHCP servers in a Failover Cluster. For every VLAN, there is a scope on the DHCP server.

     

    Since last week, some of our DHCP scopes are filling up with BAD ADDRESS entries, even to the point, that the scopes are full and no other client can get an IP address.
    When I look at the Windows 10 client, it is flapping with getting an address, refusing it, trying to get another one and so on. After about 15-20 attempts, it finally gets an address. By that time, the DHCP scope is filled with BAD ADDRESS entries.

     

    For the switch config, it is very basic:

    - dhcp relay on

    - VLANs all configured with the same two ip helper-addresses pointing to the DHCP servers 

     

    I have checked, we do not have any rogue DHCP servers in our network, which was my first idea. I even pointed the IP helper to ony one of the DHCP servers while disabling the other one.

    The strange thing is, it only happens on some of our VLANs. So not all VLANs are affected by this.

     

    After researching the whole day, I finally ran out of ideas. Maybe you guys could help me?

     

    Thanks.

     

     

     



  • 2.  RE: Aruba 8325 - IP Helper - Windows DHCP - Lots of BAD_ADDRESS

    MVP GURU
    Posted Aug 20, 2019 10:59 AM

    Do you have open a issue to TAC ?

     

    do you have looking with a capture tools on this vlan ?



  • 3.  RE: Aruba 8325 - IP Helper - Windows DHCP - Lots of BAD_ADDRESS

    MVP EXPERT
    Posted Aug 20, 2019 11:59 AM

    be sure ip clienttracking on your switch it turned of our use a delaytimer.

     

    clienttracking can give issues like you descripe and can take a horrible time of hours to find the root cause.

     

    see also https://community.arubanetworks.com/t5/Wireless-Access/DHCP-Scope-Filling-With-quot-BAD-ADDRESS-quot-Culprit/td-p/450400/page/2