Changing the network teaming failback delay fails in ESXi Host

Products

VMware vSphere ESXi VMware vSphere ESXi 6.0 VMware vSphere ESXi 7.0 VMware vSphere ESXi 8.0

Issue/Introduction

Changing the failback delay fails
Setting the failback delay to any other value does not work.

Environment

VMware vSphere ESXi 6.x
VMware vSphere ESXi 7.x
VMware vSphere ESXi 8.x

Cause

When teaming policy is in place, connections are switched to another uplink when an uplink goes down.
Connection is restored once the uplink is up again. When the primary link is flapping, this may result in packet loss due to frequent failback operation.
The TeamPolicyUpDelay setting is set to 100ms by default under Configuration > Advanced Settings > Net > Net.teampolicyupdelayTeamPolicyUpDelay defines the time, in milliseconds, that the ESX host waits after detecting that a pNIC has transitioned from a down state to an up state before the host starts using the pNIC again for network traffic. This delay helps to ensure that the pNIC has fully recovered and stabilized before it is put back into use. Usually TeamPolicyUpDelay is modified when physical switch upgrades are happening. By bringing an uplink to UP state immediately, it can impact the traffic as the connections may not reset immediately via the new uplink.
Net/TeamPolicyUpDelay setting is added to change the threshold in milliseconds (ms). This setting delays the up notification for the primary interface therefore prolong the time the active uplink stays with the standby interface.

When an up event is received, a timer is triggered to notify this. If a down event occurs when the trigger is pending, then the up notification is cancelled.

Resolution

This is resolved in ESXi 6.7 P02

While this issue is resolved in ESXi 6.7 P02, it is important to note that the configuration option causing the issue remains valid in ESXi 7.0 and ESXi 8.0.

The resolution addresses the behavior under certain conditions rather than the Configuration setting itself. Therefore ESXi 7.0 and ESXi 8.0 are included in impacted environment list to ensure clarity.

Kindly refer to NIC Teaming Policy Documents below for further details Teaming and Failover Policy

NSX-T Perspective:

Please note that the information provided in this section is NSX-T perspective.
If NSX is running on this host and using NVDS, You can also apply these changes using below command from ESXi root login.

#nsxcli -c set vswitch runtime TeamPolicyUpDelay "value"

Example: nsxcli -c set vswitch runtime TeamPolicyUpDelay 600000.

However, this will take effect at runtime and will not persist after the host rebooted the value will reset to its default.

To persist the change, please follow the steps below:

Option 1

Make changes from ESXi via vSphere console -pick host > Configure > Advanced system Settings > Net.TeamPolicyUpDelay > edit (default is 100)
Set the value you want and save by clicking ok.
Reboot host for changes to take effect (Optional: Reboot is not required for this setting to take effect on ESXi 8.0)
Once node is back online, ssh to host with root and verify the setting using below command :

[root@esx-host:~] nsxcli -c get vswitch runtime
Fri Jun 05 2026 UTC 04:15:43.171
IGMPQueries:                    2
IGMPQueryInterval:              125
IGMPRouterIP:                   0.0.0.0
IGMPV3MaxSrcIPNum:              10
IGMPVersion:                    3
MLDRouterIP:                    FE80::FFFF:FFFF:FFFF:FFFF
MLDV2MaxSrcIPNum:               10
MLDVersion:                     2
MaxRARPsPerInterval:            128
RARPAdvertisementDuration:      60
TeamPolicyUpDelay:              60000

OR

[root@esx-host:~] esxcli system settings advanced list -o  /Net/TeamPolicyUpDelay
   Path: /Net/TeamPolicyUpDelay
   Type: integer
   Int Value: 60000
   Default Int Value: 100
   Min Value: 0
   Max Value: 1800000
   String Value:
   Default String Value:
   Valid Characters:
   Description: Delay (ms) before considering an `uplink up' event relevant
   Host Specific: false
   Impact: none

Option 2

Make changes on ESXi via command line with below command

#esxcli system settings advanced set -o /Net/TeamPolicyUpDelay --int-value xxx
Example: esxcli system settings advanced set -o /Net/TeamPolicyUpDelay --int-value 300000
Reboot host for changes to take effect (Optional: Reboot is not required for this setting to take effect on ESXi 8.0)
ssh to host with root and verify the setting using below command :

[root@esx-host:~] nsxcli -c get vswitch runtime
Fri Jun 05 2026 UTC 04:15:43.171
IGMPQueries:                    2
IGMPQueryInterval:              125
IGMPRouterIP:                   0.0.0.0
IGMPV3MaxSrcIPNum:              10
IGMPVersion:                    3
MLDRouterIP:                    FE80::FFFF:FFFF:FFFF:FFFF
MLDV2MaxSrcIPNum:               10
MLDVersion:                     2
MaxRARPsPerInterval:            128
RARPAdvertisementDuration:      60
TeamPolicyUpDelay:              60000

OR

[root@esx-host:~] esxcli system settings advanced list -o  /Net/TeamPolicyUpDelay
   Path: /Net/TeamPolicyUpDelay
   Type: integer
   Int Value: 60000
   Default Int Value: 100
   Min Value: 0
   Max Value: 1800000
   String Value:
   Default String Value:
   Valid Characters:
   Description: Delay (ms) before considering an `uplink up' event relevant
   Host Specific: false
   Impact: none

Note: N-VDS is not supported on NSX 4.X version. With the release of VMware NSX 4.x N-VDS is not supported for ESXi hosts anymore.
However, if you are still using NVDS or have already migrated to VDS, this change is being made directly to ESXI and will apply to both.

Additional Information

Customer may also consider disabling the failback feature completely to allow manual switching to the primary interface per redundancy design of the environment.