Update Azure Local Network Gateway IP

updateAzureLocalNetworkGateway.ps1

Param (
    [string]$resourceGroup = "Networking-US-East-2",
    [string]$localGatewayName = "LocalGateway-HQ",
    [string]$location = "East US 2",
    [string]$lgwSubnetPrefix = "192.168.0.0/21"
)

function Get-LocalIP {
    $wc = New-Object net.webclient
    $localIP = $wc.downloadstring("http://checkip.dyndns.com") -replace "[^\d\.]"

    return $localIP
}

function Get-LocalGatewayIP ($resourceGroup, $localGatewayName) {
    $lng = Get-AzureRmLocalNetworkGateway -Name $localGatewayName -ResourceGroupName $resourceGroup

    return $lng.GatewayIpAddress
 }

function Update-LocalGateway ($resourceGroup, $localGatewayName, $localIP, $location, $addressPrefix) {
    $localGateway = New-AzureRmLocalNetworkGateway -Name $localGatewayName `
                        -ResourceGroupName $resourceGroup `
                        -Location $location `
                        -GatewayIpAddress $localIP `
                        -AddressPrefix $addressPrefix `
                        -Force `
                        -Confirm:$false
    Write-Output("$localGatewayName Local Gateway updated...")  
}
 $localIP = Get-LocalIP
 $gatewayIP = Get-LocalGatewayIP -resourceGroup $resourceGroup -localGatewayName $localGatewayName

 If ($gatewayIP -ne $localIP) {
    Update-LocalGateway -resourceGroup $resourceGroup `
                        -localGatewayName $localGatewayName `
                        -localIP $localIP `
                        -location $location `
                        -addressPrefix $lgwSubnetPrefix
}