IP address moving between two MAC Address on a Dell Switch Port

Ojo1219,

The issue you are seeing is typically caused by one of the following:

1. NIC Teaming or Bonding
If the connected device (e.g., a server or hypervisor host) is using NIC teaming, LACP, or failover bonding, it may present multiple MAC addresses on the same port depending on the active interface.
This is common in active-passive or load-balanced configurations.

2. Virtualization (e.g., Hyper-V, VMware)
Virtual machines (VMs) may have their own MAC addresses.
If VMs are migrated or restarted, the host NIC may temporarily advertise different MACs.

3. MAC Address Spoofing or Bridging
Some software (e.g., containers, firewalls, or VPNs) may bridge or spoof MAC addresses.
This can cause the switch to see multiple MACs from the same physical port.

I would start with checking for those, after that would you confirm a couple things for me.

Did this issue just start, or has it been persistent since configuration?
Does it only appear with a specific system or system type connecting?
If the effected device is removed does it happen to any other system?
Does it only happen on a specific port?

Let me know what you see, and if this helps.

Thanks for your response. 

1. HP desktop (with some important applications) is statically connected to the switch port. 

2. it’s not a VM, but a physical desktop with static IP. 

3. Not sure. We switch to different desktops, the same issue occurs; seeing different MAC addresses every time we switch out the desktop.

I joined the company a couple of years ago, and the issue has been going on since I joined.  

It only happens on this particular switch. 

I would say it happens on that specific port. 

when I removed the desktop from the port, of course that IP is removed and the multiple MAC no longer seeing on that port. Tried different desktops same issue, removed desktop completely, no issue. Must be the port or switch issue, my guess. How do I fix this? We need the port as it is one of the few ports left to use. 

Would you confirm the model switch this is on, as well as share the results of the command below?

show running-config interface

Switch#sh version
Dell Real Time Operating System Software
Dell Operating System Version:  2.0
Dell Application Software Version:  9.11(2.4)
Copyright (c) 1999-2017 by Dell Inc. All Rights Reserved.
Build Time: Fri Aug 18 04:10:12 2017
Build Path: /build/build11/SW/SRC
Dell Networking OS uptime is 7 year(s), 3 week(s), 3 day(s), 0 hour(s), 0 minute                                                                                                                                   (s)

System image file is "system://A"

System Type: S4820T
Control Processor: Freescale QorIQ P2020 with 2 Gbytes (2147483648 bytes) of mem                                                                                                                                   ory, core(s) 1.

128M bytes of boot flash memory.

  1 52-port GE/TE/FG (SE)
 56 Ten GigabitEthernet/IEEE 802.3 interface(s)
  2 Forty GigabitEthernet/IEEE 802.3 interface(s)

@DELL-Chris H ​ 

Swith#show running-config interface
!
stack-unit 0 port 48 portmode quad
!
stack-unit 0 port 52 portmode quad
!
interface TenGigabitEthernet 0/0
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/1
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/2
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/3
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/4
  no ip address
 mtu 1500
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/5
  no ip address
 mtu 1500
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/6
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/7
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/8
  ip address 20.20.20.2/30
 mtu 9216
 flowcontrol rx on tx off
 ip access-group CAtoCP in
 ip access-group CPtoCA out
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/9
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/10
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/11
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree 0 portfast
 no shutdown
!
interface TenGigabitEthernet 0/12

 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree 0 portfast
 no shutdown
!
interface TenGigabitEthernet 0/13
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/14
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/15
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/16
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/17
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/18
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 no shutdown
!
interface TenGigabitEthernet 0/19
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/20
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/21
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/22
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/23
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/24
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/25
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/26
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/27
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/28
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/29

 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/30
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/31
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/32
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/33
 description ASE_SerailIP_converters
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/34
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/35
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/36
  mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/37
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/38
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/39
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/40
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/41
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/42
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/43
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/44
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/45
  no ip address
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/46
  no ip address
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/47
  ip address 1.1.1.1/24
 mtu 12000
 flowcontrol rx on tx off
 sflow ingress-enable
 no shutdown
!
interface TenGigabitEthernet 0/48
  no ip address
 mtu 1500
!
 port-channel-protocol LACP
  port-channel 2 mode active
 no shutdown
!
interface TenGigabitEthernet 0/49
 
 no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 no spanning-tree
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/50
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 no spanning-tree
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/51
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 no spanning-tree
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/52
  no ip address
 mtu 1500
!
 port-channel-protocol LACP
  port-channel 3 mode active
 no shutdown
!
interface TenGigabitEthernet 0/53
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 no spanning-tree
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/54
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 no spanning-tree
 spanning-tree rstp edge-port
 shutdown
!
interface TenGigabitEthernet 0/55
  no ip address
 mtu 9216
 switchport
 flowcontrol rx on tx off
 no spanning-tree
 spanning-tree rstp edge-port
 shutdown
!
interface fortyGigE 0/56
 
 no ip address
 no shutdown
!
interface fortyGigE 0/60
  no ip address
 no shutdown

interface Loopback 0
 ip address 2.2.2.2/32
 ip pim sparse-mode
 no shutdown
!
interface Port-channel 1
 no ip address
 switchport
 vlt-peer-lag port-channel 1
 no shutdown
!
interface Port-channel 2
 
 no ip address
 switchport
 sflow ingress-enable
 vlt-peer-lag port-channel 2
 no shutdown
!
interface Port-channel 3
  no ip address
 switchport
 sflow ingress-enable
 vlt-peer-lag port-channel 3
 no shutdown
!
interface Port-channel 100
  no ip address
 channel-member fortyGigE 0/56,60
 no shutdown
!
interface Vlan 1
  name DEFAULT VLAN
!untagged TenGigabitEthernet 0/6,25
!untagged Port-channel 1,100
 no shutdown
!
interface Vlan 102
   ip address 10.123.102.4/29
 untagged Port-channel 2-3
 no shutdown
!
interface Vlan 103
   ip address 10.123.103.2/24
 untagged TenGigabitEthernet 0/0-1,7,9-19,21-24,26-31
 ip pim sparse-mode
!
 vrrp-group 103

  priority 200
  virtual-address 10.123.103.1
 no shutdown
!
interface Vlan 104

 ip address 10.123.104.2/24
 untagged TenGigabitEthernet 0/40-44,49-51,53-55
!
 vrrp-group 104
  
  priority 200
  virtual-address 10.123.104.1
 no shutdown
!
interface Vlan 107

 ip address 10.123.x.2/24
 untagged TenGigabitEthernet 0/2-5,20,32-39
!
 vrrp-group 107

  priority 200
  virtual-address 10.123.x.1
 no shutdown

I am not seeing anything in the config that stands out. You could try updating the OS on the switch, found here.   I am not certain there is much we can do on the forums not having access to it, so you may want to consider calling in for support, as they can directly work on the switch.

Ok thanks. Appreciate 

Thank you all. The issue is with the desktop. I have replaced the desktop, and the issue no longer occurs.