FX2 IOA constantly requesting DHCP, exhausting vlan1 scope with BAD_ADDRESS

Question

I have a Win 2008 R2 (and then upgraded to 2012 R2) DHCP server which was getting loads of BAD_ADDRESS filling up the scope in vlan1. All other scopes for other vlans were unaffected. Wireshark indicated a the dell mac address for the management of IOA which the switch showed on our PortChannel3 (two 10gbe fiber optic interfaces).

But in our IOA config we have a static IP set of 10.1.0.103/16. The DHCP server is at 10.1.1.1/16 and also offers ip's in other scopes (vlan2 10.2.1.1/16, vlan3 10.3.1.1/16, vlan4 10.4.1.1/16 and vlan5 10.5.1.1/16).

I had to put the Dell IOA mac address in the DHCP deny filter list and enable it so that it would not respond and plug up our address space full of BAD_ADDRESS.

Any idea why the IOA is doing dhcp requests even though we set it for a static IP?

kjstech · Accepted Answer

Ok i think I may have found something. On the switch config I am able to access it by ssh to the CMC and issuing a connect command to switch-1.

I see that in show run it has this entry

interface Vlan 1

ip address dhcp

mtu 2500

no shutdown

So I conf t and enter

no ip address dhcp

Now I'm running wireshark and havent seen this mac address in my filter for bootp at all yet. They may have been the problem. What's weird is who knows why if it was on DHCP, that our server wouldn't of just given it an IP address and be done with it. Who knows why every minute the IOA kept DHCP and our server kept declining it then marking it a bad address.

Anyway I don't need an ip address on vlan1 on the IOA because were not having it doing any L3. I also already have an IP address on management ethernet 0/0 but I can't manage it anyway to its direct IP unless I shutdown the Gig e port that the CMC chassis management is plugged into on our core switch. So I manage it by ssh to the CMC and issuing a connect command.

The other IOA is on its own isolated Brocade switch with its own IP scheme and everything, which is NOT connected to our lan. This brocade switch is simply an IP storage network for NFS to virtual machines and our backup appliance.

Daniel My · Answer

Hello

The manual has an extensive write-up about the DHCP client. I would suggest using the various commands mentioned in that section and the command line reference guide to see which interface is making the DHCP requests. You can use the no ip address dhcp command to disable the DHCP client on an interface.

I would also check the DHCP scopes to make sure that 10.1.0.103/16 is not part of a pool. I would also check to see if it is in any list.

the switch showed on our PortChannel3 (two 10gbe fiber optic interfaces).

If you are running multiple port channels/LAGs to the IOA then make sure they are configured properly on the IOA. By default all 4 ports on the IOA are in a port channel.

https://www.dell.com/support/home/us/en/19/product-support/product/poweredge-fx2/manuals

Thanks

kjstech · Answer

For some reason when I went to reply it made a new thread, please take it here... en.community.dell.com/.../19674729

kjstech · Answer

Thank you for the command reference. I will look through that, however I think there is a bug in IOA software 9.8. Look at the CMC setup tab of the IOA's and you will see that Enable DHCP is UNCHECKED and a static IP address is entered. If DHCP is unchecked, its my understanding that this management MAC address should not be showing up in wireshark captures trying to retrieve dhcp addresses every couple of seconds.

Filtering this MAC from DHCP is a good workaround for now but it still unnecessary traffic and something to remember if in the future we move DHCP servers to ensure the mac filter is still in place. Luckily when I moved DHCP servers the Windows Server migration tools did move this over. Once the filter was in place and all the "BAD_ADDRESS" were deleted, no more re-appeared.

dchurcorb · Answer

Just wanted to say thanks.  Was running into the same problem.  I disabled DHCP on VLAN 1 on the 2 IOA's on the FX Chassis, and problem went away.  Was going crazy with this.

jsmithers311 · Answer

Can anyone provide the actual cli command for this? Should this be ran on the CMC? Thanks,  - Jason

jsmithers311 · Answer

Can anyone provide the commands to fix this? I am having the same issue. Dell is not aware, it seems.  - Jason

kjstech · Answer

Its been some time since I did this, but I think you just log into the IOAggrigator "switch" with something like PuTTY and do commands like you would on cisco:

conf t

interface vlan1

no ip address dhcp

end

wr mem

jsmithers311 · Answer

Yep, that did the trick. Many thanks and much appreciated.  - Jason

PowerEdge Hardware General

FX2 IOA constantly requesting DHCP, exhausting vlan1 scope with BAD_ADDRESS

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