param([string]$switchName, [int]$addressIndex)
$HostVMAdapter = Hyper-V\Get-VMNetworkAdapter -ManagementOS -SwitchName $switchName | Select-Object -First 1
if ($HostVMAdapter){
  $HostNetAdapter = Get-NetAdapter | Where-Object { $_.DeviceId -eq $HostVMAdapter.DeviceId }
  if ($HostNetAdapter){
    $HostNetAdapterConfiguration = @(Get-NetIPAddress -AddressFamily IPv4 -InterfaceIndex $HostNetAdapter.InterfaceIndex | Where-Object SuffixOrigin -notmatch "Link")
    if ($HostNetAdapterConfiguration){
      return @($HostNetAdapterConfiguration.IpAddress)[$addressIndex]
    }
  }
} else {
  $HostNetAdapterConfiguration=@(Get-NetIPAddress -CimSession $env:computername -AddressFamily IPv4 | Where-Object { ( $_.InterfaceAlias -notmatch 'Loopback' ) -and ( $_.SuffixOrigin -notmatch "Link" )})
  if ($HostNetAdapterConfiguration) {
    return @($HostNetAdapterConfiguration.IpAddress)[$addressIndex]
  } else {
    return $false
 }
}

PS C:\Users\jshbrntt> Hyper-V\Get-VMNetworkAdapter -ManagementOS -SwitchName 'Default Switch'

Name                   IsManagementOs VMName SwitchName     MacAddress   Status IPAddresses
----                   -------------- ------ ----------     ----------   ------ -----------
Container NIC a4f898fb True                  Default Switch 00155DFDCF45 {Ok}
Container NIC a8fe71a1 True                  Default Switch 00155D3A43A4 {Ok}

PS C:\Users\jshbrntt> $HostVMAdapter1 = Hyper-V\Get-VMNetworkAdapter -ManagementOS -SwitchName 'Default Switch' | Select-Object -First 1
PS C:\Users\jshbrntt> $HostVMAdapter2 = Hyper-V\Get-VMNetworkAdapter -ManagementOS -SwitchName 'Default Switch' | Select-Object -Skip 1
PS C:\Users\jshbrntt> Get-NetAdapter -IncludeHidden | Where-Object { $_.DeviceId -eq $HostVMAdapter1.DeviceId }

Name                      InterfaceDescription                    ifIndex Status       MacAddress             LinkSpeed
----                      --------------------                    ------- ------       ----------             ---------
vEthernet (nat)           Hyper-V Virtual Ethernet Adapter             58 Up           00-15-5D-FD-CF-45        10 Gbps

PS C:\Users\jshbrntt> Get-NetAdapter -IncludeHidden | Where-Object { $_.DeviceId -eq $HostVMAdapter2.DeviceId }

Name                      InterfaceDescription                    ifIndex Status       MacAddress             LinkSpeed
----                      --------------------                    ------- ------       ----------             ---------
vEthernet (Default Swi... Hyper-V Virtual Ethernet Adapter #2          63 Up           00-15-5D-3A-43-A4        10 Gbps

PS C:\Users\jshbrntt> ipconfig
#...
Ethernet adapter vEthernet (Default Switch):

   Connection-specific DNS Suffix  . :
   Link-local IPv6 Address . . . . . : fe80::4cb5:7bcd:a676:346d%63
   IPv4 Address. . . . . . . . . . . : 172.26.208.1
   Subnet Mask . . . . . . . . . . . : 255.255.240.0
   Default Gateway . . . . . . . . . :
#...
Ethernet adapter vEthernet (nat):

   Connection-specific DNS Suffix  . :
   Link-local IPv6 Address . . . . . : fe80::d945:a2e:a496:eb94%58
   IPv4 Address. . . . . . . . . . . : 172.26.160.1
   Subnet Mask . . . . . . . . . . . : 255.255.240.0
   Default Gateway . . . . . . . . . :

PS C:\Users\jshbrntt> packer version
Packer v1.8.5

Your version of Packer is out of date! The latest version
is 1.8.6. You can update by downloading from www.packer.io/downloads

PS C:\Users\joshua.barnett> packer plugins installed
C:\Users\jshbrntt\AppData\Roaming\packer.d\plugins\github.com\hashicorp\hyperv\packer-plugin-hyperv_v1.0.4_x5.0_windows_amd64.exe