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Last reply by 08-28-2022 Unsolved
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Dell FX2 FN 410S IO Aggregator mgmt issue when vlan 1 is allowed on trunk port

New to the FN 410S IOA but I've noticed that I set a management IP on IOA A1 if and A2 to  I connect a fiber optic cable from an SFP on port 9 from A1 to a 10gbps port on Cisco 3750x2 sfp.  Link comes up at 10gig full, great.  I need to pass a few VLANs to uplink this chassis to our network, so the Cisco config is like this:

interface TenGigabitEthernet9/1/1
description Dell FX2 IOA 10GbE A1 Port 9
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,5,10,20,21,172
switchport mode trunk
ip access-group acl1 in
mls qos trust dscp

I want my VM's hosted within the FX2 chassis to have access to these vlans:

1 - servers, 5 - wireless, 10 - san, 20 dmz, 21 dmz2, 172 voice.

However once this is setup I can no longer manage the IOA management IP on  Ping times out.  The Cisco switch logs seems to indicate mac flapping between Te9/1/1 (the IOA) and Gi1/0/11 (The CMC Management port).  However if I remove vlan 1 from this switchport and instead use this line on the Cisco side:

switchport trunk allowed vlan 5,10,20,21,172

I can then manage the IOA IP address at again.  However this means any VM's I start to provision (or server blades) won't pass traffic through to VLAN 1 which is our server / pc lan.

Is there an alternate configuration for this?

Replies (10)


VLAN 1 is an untagged VLAN by default and so that may be causing an issue, it typically is just for management. Page 18


DELL-Josh Cr
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Did you ever find a resolution to this issue?  I'm working with a new out-of-the-box FX2 installation with what I thought would be a plain vanilla installation.  VLAN1 untagged, all others passed through, one uplink per IOM.  I'm seeing the exact behavior described here, where the IOM management IP (untagged on VLAN1) is constantly flapping between the IOM uplink port and the CMC management port.

Not applicable

What firmware is the switch running? I will help do some research on this, see if we can find a resolution.


Any update on this?


Hello, I am seeing this issue with (2) FN 410S IOAs connected to a pair of Dell S4128F-ON switches via a VLT port channel. When removing VLAN 1 from the port channel interfaces on the switches, the problem disappears. The FX2 CMC interface is connected to one the switches on access mode port in VLAN 1, but I would also like to have VLAN 1 on the IOA uplinks. Why in the world would the IOA start flapping its OOB management interface mac on the LAG?


I just ran into this issue in my Lab.  A very simple configuration of an FX2 chassis that I'm trying to uplink to an existing PowerConnect 6224 w/ 10G module (xg3 & xg4) for connection to the Lab systems.  The chassis mgmt interface connects to port e0/1 on the switch and I can manage the chassis, iDRACs, IOMs, etc. from my laptop on e0/2.  When I try to connect the IOM-A module external port (te 0/12) to the PC6224 (xg4), I got nothing.  Then I discovered I need to set the te0/12 to "mode switchport".  I can now ping all the ESXi hosts mgmt IPs, but I get ~50% packet loss trying to ping the IOM-A mgmt IP address.  

So, how is this really an OutOfBand Mgmt interface on the CMC if it's being pushed up to my switch via the uplink on te0/12?  Should I change the default VLAN of all the ports on IOM-A  (te 0/1-0/12) from 1 to 2 then?  I hope to post back after further testing.

The IOM is in "full switch" mode.

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If anyone else comes across this issue I just managed to solve it for our environment

The IP addresses of the CMC, the iDRACs and the FN IOM's had to be moved to another VLAN that doesn't traverse through the uplink/port channels on the FN's

This allows you to have vlan 1 traverse the trunks

It seems there is back end communication between the CMC management port and the FN's that as stated by the OP causes flapping on upstream switches.

Luckily we had another VLAN that we didn't want to host any VM's on so could use this for the management addresses


Here is the short fix:

interface ManagementEthernet 0/0
no ip address


Thanks for offering this solution @alik996  -- can you offer a little bit of explanation?  I don't want to screw this up.  

These commands should be issued on each FN 410s module, correct?  Will the FN 410s modules continue to be available via CMC ethernet uplink?   I am new to Dell networking and am unclear about the scope of ManagementEthernet and what is on that.  Just want to make sure I'm not going to block and lock myself out from anything.

On the other hand, it might be more flexible for me if I could access everything via a designated FN 410s uplink port instead of the CMC port, if that is at all possible.  (I'm not sure if there is a way to get the CMC listening via the FN410s somehow.  I think the IDRAC's can be set to LOM1/LOM2 to accomplish this, and it sounds like the FN410s interfaces are already on both?)

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