Monthly Archives: February 2015

Windows server 2012 R2 – A port on the virtual switch has the same MAC as one of the underlying team members on Team Nic Microsoft Network Adapter Multiplexor Driver

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If you have two or more NICs joined in a Team by using Windows server teaming solution and then you use this Team as a base for Virtual switch in Hyper-V and you enable “Allow management operating system to share this network adapter” like:

003 004 005

you will find warnings in system Event log:

A port on the virtual switch has the same MAC as one of the underlying team members on Team Nic Microsoft Network Adapter Multiplexor Driver

001

Check your NICs by using Powershell cmdlet: get-netadapter | ft Name,MacAddress

002

You need to change MAC addresses of your Virtual Switch management interface (vEthernet (xxx)) by using Powershell cmdlet: set-netadapter -name “vEthernet (XXX)” -macaddress xx:xx:xx:xx:xx:xx

007

and MAC addresses of your network cards (in my case 4 NICs) you can leave Team interface mac address alone…

009

There will be no errors in Event log any more 🙂

HP DL380 G8 – Windows server 2012 R2 NIC Teaming (HP Ethernet 1Gb 4-port 331FLR Adapter) – stops working after some time…

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I have two HP DL 380 G8 servers with Windows server 2012 R2 OS. I have formed NIC teams by using Windows – built-in NIC teaming.

It Works perfectly but after a week or two teams stop working – the only mode to get server online again is to disable and re-enable physical network cards.

Server uses: HP Ethernet 1Gb 4-port 331FLR Adapter – I have upgraded firmware to latest version (that was available on 1.2.2015) and also updated drivers – but the problem persist.

For a current workaround I have scripted a powershell script that checks connectivity and cycle network adapters:

if (Test-Connection 8.8.8.8 -Count 1 -ErrorAction SilentlyContinue)
{
Add-Content C:watchdogresult.txt “`nUP”
}
else
{
Disable-NetAdapter -Name “Ethernet” -Confirm:$false
Enable-NetAdapter -Name “Ethernet”
Disable-NetAdapter -Name “Ethernet 2” -Confirm:$false
Enable-NetAdapter -Name “Ethernet 2”
Disable-NetAdapter -Name “Ethernet 3” -Confirm:$false
Enable-NetAdapter -Name “Ethernet 3”
Disable-NetAdapter -Name “Ethernet 4” -Confirm:$false
Enable-NetAdapter -Name “Ethernet 4”
$datenow = Get-Date
$datesult = “`n” + $datenow + ” Repaired”
$datesult | Add-Content C:watchdogresult.txt
}

Save as script.ps1

and create a task scheduler task with parameters:

Security options:
Run whether user is logged on or not
Run with highest privileges

Trigger:
Daily
Repeat every 5 minutes for 1 day

Action:
Start program: powershell
Add argument: -ExecutionPolicy bypass -file “C:watchdognet.ps1”

Your txt file should have similar entries – UP if network is working and Repaired with date and time if team failed and was repaired by scrpt:

UP
UP
UP
02/01/2015 12:25:49 Repaired
UP
UP