Get-Network.ps1

<#
.SYNOPSIS
Determines the most likely candidate for the active Internet-specific network adapter on this
machine.  All other adpaters such as tunneling and loopbacks are ignored.  Only connected IP
adapters are considered.
#>

param(
	[switch] $preferred,	# just return the preferred address
	[switch] $addresses,	# return a list of host addresses
	[switch] $verbose)		# verbose report

Begin
{
	function Get-Addresses ()
	{
		$addresses = @()
		if ([Net.NetworkInformation.NetworkInterface]::GetIsNetworkAvailable())
		{
			[Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces() | % `
			{
				$props = $_.GetIPProperties()

				$address = $props.UnicastAddresses `
					| ? { $_.Address.AddressFamily -eq 'InterNetwork' } `
					| select -first 1 -ExpandProperty Address

				if ($address)
				{
					$addresses += $address.IPAddressToString
				}
			}
		}

		$addresses
	}

	function Get-Preferred ()
	{
		$prefs = @()
		if ([Net.NetworkInformation.NetworkInterface]::GetIsNetworkAvailable())
		{
			[Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces() | % `
			{
				if (($_.NetworkInterfaceType -ne 'Loopback') -and ($_.OperationalStatus -eq 'Up'))
				{
					$props = $_.GetIPProperties()
 
					$address = $props.UnicastAddresses `
						| ? { $_.Address.AddressFamily -eq 'InterNetwork' } `
						| select -first 1 -ExpandProperty Address

					$DNSServer = $props.DnsAddresses `
						| ? { $_.AddressFamily -eq 'InterNetwork' } `
						| select -first 1 -ExpandProperty IPAddressToString

					if ($address -and $DNSServer)
					{
						$prefs += $address.IPAddressToString
					}
				}
			}
		}

		if ($prefs.Length -gt 0)
		{
			return $prefs[0]
		}

		return $null
	}

	function Get-Information ()
	{
		$preferred = $null
		$items = @()
		if ([Net.NetworkInformation.NetworkInterface]::GetIsNetworkAvailable())
		{
			[Net.NetworkInformation.NetworkInterface]::GetAllNetworkInterfaces() | % `
			{
				if ($_.NetworkInterfaceType -ne 'Loopback')
				{
					$item = New-Object PSObject -Property @{
						Address         = $null
						PhysicalAddress = $_.GetPhysicalAddress().ToString()
						DNSServer       = $null
						Gateway         = $null
						Description     = $null
						DnsSuffix       = $null
						BytesReceived   = 0
						BytesSent       = 0
						Status          = $_.OperationalStatus
						Type            = $_.NetworkInterfaceType
					}
			
					$props = $_.GetIPProperties()

					$item.Address = $props.UnicastAddresses `
						| ? { $_.Address.AddressFamily -eq 'InterNetwork' } `
						| select -first 1 -ExpandProperty Address

					$item.DNSServer = $props.DnsAddresses `
						| ? { $_.AddressFamily -eq 'InterNetwork' } `
						| select -first 1 -ExpandProperty IPAddressToString

					$item.Gateway = $props.GatewayAddresses `
						| ? { $_.Address.AddressFamily -eq 'InterNetwork' } `
						| select -first 1 -ExpandProperty Address

					if ($verbose)
					{
						$stats = $_.GetIPv4Statistics() | Select -first 1
						$item.BytesReceived = $stats.BytesReceived
						$item.BytesSent = $stats.BytesSent
					}

					$item.Description = $_.Name + ', ' + $_.Description
					$item.DnsSuffix = $props.DnsSuffix
					if (($props.DnsSuffix -ne $null) -and ($props.DnsSuffix.Length -gt 0))
					{
						if ($item.Type.ToString().StartsWith('Wireless'))
						{
							$ssid = netsh wlan show interfaces | Select-String '\sSSID'
							if ($ssid)
							{
								$profile = $ssid.ToString().Split(':')[1].Trim()
								if ($profile) { $item.Description += (', ' + $profile) }
							}
						}
						else
						{
							$item.Description += (', ' + $props.DnsSuffix)
						}
					}

					if ((!$preferred) -and ($item.Status -eq 'Up') -and $item.Address -and $item.DNSServer)
					{
						$preferred = $item.Address
					}

					$items += $item
				}
			}
		}

		@{
			Preferred = $preferred
			Items = $items
		}
	}

	function Show-Preferred ($preferred)
	{
		Write-Host
		if ($preferred -eq $null)
		{
			Write-Host ('{0} Preferred address is unknown' -f $env:COMPUTERNAME) -ForegroundColor DarkGreen
		}
		else
		{
			Write-Host ("{0} Preferred address is {1}" -f $env:COMPUTERNAME, $preferred) -ForegroundColor Green
		}
	}

	function Get-ForeColor ($item, $preferred)
	{
		if ($item.Status -ne 'Up') { @{ foregroundcolor='DarkGray' } }
		elseif ($item.Address -eq $preferred) { @{ foregroundcolor='Green' } }
		elseif ($item.Type -match 'Wireless') { @{ foregroundcolor='Cyan' } }
		elseif ($item.Description -match 'Bluetooth') { @{ foregroundcolor='DarkCyan' } }
		else { @{ } }
	}

	function Show-Information ($info)
	{
		Write-Host
		Write-Host 'Address         DNS Server      Gateway         Interface'
		Write-Host '-------         ----------      -------         ---------'
		$info.Items | % `
		{
			$line = ("{0,-15} {1,-15} {2,-15} {3}" -f $_.Address, $_.DNSServer, $_.Gateway, $_.Description)
			$hash = Get-ForeColor $_ $info.Preferred
			Write-Host $line @hash
		}
	}

	function Show-Verbose ($info)
	{
		Write-Host
		Write-Host 'IP/DNS/Gateway   Interface Details'
		Write-Host '--------------   -----------------'
		$info.Items | % `
		{
			for ($i = 10; $i -gt 0; $i -= 2) { $_.PhysicalAddress = $_.PhysicalAddress.insert($i, '-') }
			$hash = Get-ForeColor $_ $info.Preferred

			Write-Host ("{0,-15}  {1}" -f $_.Address, $_.Description) @hash
			Write-Host ("{0,-15}  Physical Address.. {1}" -f $_.DNSServer, $_.PhysicalAddress) -ForegroundColor DarkGray
			Write-Host ("{0,-15}  Type.............. {1}" -f $_.Gateway, $_.Type) -ForegroundColor DarkGray

			if ($_.Status -eq 'Up')
			{
				Write-Host ("{0,16} Bytes Sent........ {1:N0}" -f '',$_.BytesSent) -ForegroundColor DarkGray
				Write-Host ("{0,16} Bytes Received.... {1:N0}" -f '',$_.BytesReceived) -ForegroundColor DarkGray

				if ($_.DnsSuffix)
				{
					Write-Host ("{0,16} DnsSuffix......... {1}" -f '',$_.DnsSuffix) -ForegroundColor DarkGray
				}
			}

			Write-Host
		}
	}
}
Process
{
	if ($preferred)
	{
		return Get-Preferred
	}

	if ($addresses)
	{
		return Get-Addresses
	}

	$info = Get-Information
	if ($info -and $info.Items -and $info.Items.Count -gt 0)
	{
		Show-Preferred $info.Preferred

		if ($verbose)
		{
			Show-Verbose $info
		}
		else
		{
			Show-Information $info
		}
	}
	else
	{
		Write-Host 'Network unavailable' -ForegroundColor Red
	}
}

<#
    ... This is a whole lot less code but is much slower then the code above 

$candidates = @()
Get-NetIPConfiguration | % `
{
	$dns = $_.DNSServer | ? { $_.AddressFamily -eq 2 } | select -property ServerAddresses | select -first 1
	$ifx = $_.InterfaceAlias + ', ' + $_.InterfaceDescription
	if ($_.NetProfile.Name -notmatch 'Unidentified') { $ifx += (', ' + $_.NetProfile.Name) }

	$candidates += New-Object psobject -Property @{
		Address = $_.IPv4Address.IPAddress
		DNSServer = [String]::Join(',', $dns.ServerAddresses)
		Gateway = $_.IPv4DefaultGateway.NextHop
		Interface = $ifx
	}
}
#>