Migrate Azure Firewall configurations to Azure Firewall policy using PowerShell

Article
08/12/2024
You can use an Azure PowerShell script to migrate existing Azure Firewall configurations to an Azure Firewall policy resource. You can then use Azure Firewall Manager to deploy the policy.
The AZFWMigrationScript.ps1 script creates a FirewallPolicy with three RuleCollectionGroup objects for ApplicationRuleCollections, NetworkRuleCollections, and NatRuleCollections respectively.
A RuleCollectionGroup is a new top-level grouping for rule collections for future extensibility. Using the above defaults is recommended and is done automatically from the Portal.
The beginning of the script defines the source firewall name and resource group and the target policy name and location. Change these values as appropriate for your organization.
Migration script

Modify the following script to migrate your firewall configuration.
#Input params to be modified as needed
$FirewallResourceGroup = "AzFWMigrateRG"
$FirewallName = "azfw"
$FirewallPolicyResourceGroup = "AzFWPolicyRG"
$FirewallPolicyName = "fwpolicy"
$FirewallPolicyLocation = "ChinaNorth2"
$DefaultAppRuleCollectionGroupName = "ApplicationRuleCollectionGroup"
$DefaultNetRuleCollectionGroupName = "NetworkRuleCollectionGroup"
$DefaultNatRuleCollectionGroupName = "NatRuleCollectionGroup"
$ApplicationRuleGroupPriority = 300
$NetworkRuleGroupPriority = 200
$NatRuleGroupPriority = 100
$InvalidCharsPattern = "[']"

# Helper functions for translating ApplicationProtocol and ApplicationRule
Function GetApplicationProtocolsString
{
  Param([Object[]] $Protocols)
  $output = ""
  ForEach ($protocol in $Protocols)
  {
    $output += $protocol.ProtocolType + ":" + $protocol.Port + ","
  }
  return $output.Substring(0, $output.Length - 1)
}
Function GetApplicationRuleCmd
{
  Param([Object] $ApplicationRule)
  $cmd = "New-AzFirewallPolicyApplicationRule"
  $parsedName = ParseRuleName($ApplicationRule.Name)
  $cmd = $cmd + " -Name " + "'" + $parsedName + "'"
  if ($ApplicationRule.SourceAddresses)
  {
    $ApplicationRule.SourceAddresses = $ApplicationRule.SourceAddresses -join ","
    $cmd = $cmd + " -SourceAddress " + $ApplicationRule.SourceAddresses
  }
  elseif ($ApplicationRule.SourceIpGroups)
  {
    $ApplicationRule.SourceIpGroups = $ApplicationRule.SourceIpGroups -join ","
    $cmd = $cmd + " -SourceIpGroup " + $ApplicationRule.SourceIpGroups
  }
  if ($ApplicationRule.Description)
 {
    $cmd = $cmd + " -Description " + "'" + $ApplicationRule.Description + "'"
  }
  if ($ApplicationRule.TargetFqdns)
  {
    $protocols = GetApplicationProtocolsString($ApplicationRule.Protocols)
    $cmd = $cmd + " -Protocol " + $protocols
    $AppRule = $($ApplicationRule.TargetFqdns) -join ","
    $cmd = $cmd + " -TargetFqdn " + $AppRule
  }
  if ($ApplicationRule.FqdnTags)
  {
    $cmd = $cmd + " -FqdnTag " + "'" + $ApplicationRule.FqdnTags + "'"
  }
  return $cmd
}
Function ParseRuleName
{
	Param([Object] $RuleName)
	if ($RuleName -match $InvalidCharsPattern) {
		$newRuleName = $RuleName -split $InvalidCharsPattern -join ""
		Write-Host "Rule $RuleName contains an invalid character. Invalid characters have been removed, rule new name is $newRuleName. " -ForegroundColor Yellow
		return $newRuleName 
	}
	return $RuleName
}
If (!(Get-AzResourceGroup -Name $FirewallPolicyResourceGroup))
{
  New-AzResourceGroup -Name $FirewallPolicyResourceGroup -Location $FirewallPolicyLocation
}
$azfw = Get-AzFirewall -Name $FirewallName -ResourceGroupName $FirewallResourceGroup
Write-Host "creating empty firewall policy"
if ($azfw.DNSEnableProxy) {
  $fwDnsSetting = New-AzFirewallPolicyDnsSetting -EnableProxy
  $fwp = New-AzFirewallPolicy -Name $FirewallPolicyName -ResourceGroupName $FirewallPolicyResourceGroup -Location $FirewallPolicyLocation -ThreatIntelMode $azfw.ThreatIntelMode -DnsSetting $fwDnsSetting -Force
}
else {
  $fwp = New-AzFirewallPolicy -Name $FirewallPolicyName -ResourceGroupName $FirewallPolicyResourceGroup -Location $FirewallPolicyLocation -ThreatIntelMode $azfw.ThreatIntelMode
}
Write-Host $fwp.Name "created"

# Translate ApplicationRuleCollection
Write-Host "creating " $azfw.ApplicationRuleCollections.Count " application rule collections"
If ($azfw.ApplicationRuleCollections.Count -gt 0)
{
  $firewallPolicyAppRuleCollections = @()
  ForEach ($appRc in $azfw.ApplicationRuleCollections)
  {
    If ($appRc.Rules.Count -gt 0)
    {
      Write-Host "creating " $appRc.Rules.Count " application rules for collection " $appRc.Name
      $firewallPolicyAppRules = @()
      ForEach ($appRule in $appRc.Rules)
      {
        $cmd = GetApplicationRuleCmd($appRule)
        $firewallPolicyAppRule = Invoke-Expression $cmd
        Write-Host "Created Application Rule: " $firewallPolicyAppRule.Name
        $firewallPolicyAppRules += $firewallPolicyAppRule
      }
      $fwpAppRuleCollection = New-AzFirewallPolicyFilterRuleCollection -Name $appRC.Name -Priority $appRC.Priority -ActionType $appRC.Action.Type -Rule $firewallPolicyAppRules
      Write-Host "Created Application Rule Collection: "  $fwpAppRuleCollection.Name
    }
    $firewallPolicyAppRuleCollections += $fwpAppRuleCollection
  }
  $appRuleGroup = New-AzFirewallPolicyRuleCollectionGroup -Name $DefaultAppRuleCollectionGroupName -Priority $ApplicationRuleGroupPriority -RuleCollection $firewallPolicyAppRuleCollections -FirewallPolicyObject $fwp
  Write-Host "Created Application Rule Collection Group: "  $appRuleGroup.Name
}

# Translate NetworkRuleCollection
Write-Host "creating " $azfw.NetworkRuleCollections.Count " network rule collections"
If ($azfw.NetworkRuleCollections.Count -gt 0)
{
  $firewallPolicyNetRuleCollections = @()
  ForEach ($rc in $azfw.NetworkRuleCollections)
  {
    If ($rc.Rules.Count -gt 0)
    {
      Write-Host "creating " $rc.Rules.Count " network rules for collection "  $rc.Name
      $firewallPolicyNetRules = @()
      ForEach ($rule in $rc.Rules)
      {
        $parsedName = ParseRuleName($rule.Name)
        If ($rule.SourceAddresses)
        {
          If ($rule.DestinationAddresses)
          {
            $firewallPolicyNetRule = New-AzFirewallPolicyNetworkRule -Name $parsedName -SourceAddress $rule.SourceAddresses -DestinationAddress $rule.DestinationAddresses -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
          }
          elseif ($rule.DestinationIpGroups)
          {
            $firewallPolicyNetRule = New-AzFirewallPolicyNetworkRule -Name $parsedName -SourceAddress $rule.SourceAddresses -DestinationIpGroup $rule.DestinationIpGroups -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
          }
          elseif ($rule.DestinationFqdns)
          {
            $firewallPolicyNetRule = New-AzFirewallPolicyNetworkRule -Name $parsedName -SourceAddress $rule.SourceAddresses -DestinationFqdn $rule.DestinationFqdns -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
          }
        }
        elseif ($rule.SourceIpGroups)
        {
          If ($rule.DestinationAddresses)
          {
            $firewallPolicyNetRule = New-AzFirewallPolicyNetworkRule -Name $parsedName -SourceIpGroup $rule.SourceIpGroups -DestinationAddress $rule.DestinationAddresses -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
          }
          elseif ($rule.DestinationIpGroups)
          {
            $firewallPolicyNetRule = New-AzFirewallPolicyNetworkRule -Name $parsedName -SourceIpGroup $rule.SourceIpGroups -DestinationIpGroup $rule.DestinationIpGroups -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
          }
          elseif ($rule.DestinationFqdns)
          {
            $firewallPolicyNetRule = New-AzFirewallPolicyNetworkRule -Name $parsedName -SourceIpGroup $rule.SourceIpGroups -DestinationFqdn $rule.DestinationFqdns -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
          }
        }
        Write-Host "Created network rule: " $firewallPolicyNetRule.Name
        $firewallPolicyNetRules += $firewallPolicyNetRule
      }
      $fwpNetRuleCollection = New-AzFirewallPolicyFilterRuleCollection -Name $rc.Name -Priority $rc.Priority -ActionType $rc.Action.Type -Rule $firewallPolicyNetRules
      Write-Host "Created Network Rule Collection: "  $fwpNetRuleCollection.Name
    }
    $firewallPolicyNetRuleCollections += $fwpNetRuleCollection
  }
  $netRuleGroup = New-AzFirewallPolicyRuleCollectionGroup -Name $DefaultNetRuleCollectionGroupName -Priority $NetworkRuleGroupPriority -RuleCollection $firewallPolicyNetRuleCollections -FirewallPolicyObject $fwp
  Write-Host "Created Network Rule Collection Group: "  $netRuleGroup.Name
}

# Translate NatRuleCollection
# Hierarchy for NAT rule collection is different for AZFW and FirewallPolicy. In AZFW you can have a NatRuleCollection with multiple NatRules
# where each NatRule will have its own set of source , dest, translated IPs and ports.
# In FirewallPolicy a NatRuleCollection has a set of rules which has one condition (source and dest IPs and Ports) and the translated IP and ports
# as part of NatRuleCollection.
# So when translating NAT rules we will have to create separate ruleCollection for each rule in AZFW and every ruleCollection will have only 1 rule.
Write-Host "creating " $azfw.NatRuleCollections.Count " NAT rule collections"
If ($azfw.NatRuleCollections.Count -gt 0)
{
  $firewallPolicyNatRuleCollections = @()
  $priority = 100
  ForEach ($rc in $azfw.NatRuleCollections)
  {
    $firewallPolicyNatRules = @()
    If ($rc.Rules.Count -gt 0)
    {
      Write-Host "creating " $rc.Rules.Count " nat rules for collection "  $rc.Name
      ForEach ($rule in $rc.Rules) 
			{
				$parsedName = ParseRuleName($rule.Name)
				If ($rule.SourceAddresses) 
				{
					$firewallPolicyNatRule = New-AzFirewallPolicyNatRule -Name $parsedName -SourceIpGroup  $rule.SourceAddresses -TranslatedAddress $rule.TranslatedAddress -TranslatedPort $rule.TranslatedPort -DestinationAddress $rule.DestinationAddresses -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
				}
        elseif ($rule.SourceIpGroups)
        {
					$firewallPolicyNatRule = New-AzFirewallPolicyNatRule -Name $parsedName -SourceIpGroup  $rule.SourceIpGroups -TranslatedAddress $rule.TranslatedAddress -TranslatedPort $rule.TranslatedPort -DestinationAddress $rule.DestinationAddresses -DestinationPort $rule.DestinationPorts -Protocol $rule.Protocols
        }
				Write-Host "Created NAT rule: " $firewallPolicyNatRule.Name
        $firewallPolicyNatRules += $firewallPolicyNatRule
      }

      $natRuleCollectionName = $rc.Name
      $fwpNatRuleCollection = New-AzFirewallPolicyNatRuleCollection -Name $natRuleCollectionName -Priority $priority -ActionType $rc.Action.Type -Rule $firewallPolicyNatRules
      $priority += 1
      Write-Host "Created NAT Rule Collection: "  $fwpNatRuleCollection.Name
      $firewallPolicyNatRuleCollections += $fwpNatRuleCollection
    }
  }
  $natRuleCollectionGroup = New-AzFirewallPolicyRuleCollectionGroup -Name $DefaultNatRuleCollectionGroupName -Priority $NatRuleGroupPriority -RuleCollection $firewallPolicyNatRuleCollections -FirewallPolicyObject $fwp
  Write-Host "Created NAT Rule Collection Group: "  $natRuleCollectionGroup.Name
}
Next steps

Learn more about Azure Firewall Manager deployment: Azure Firewall Manager deployment overview.
Migrate Azure Firewall configurations to Azure Firewall policy using PowerShell

Migration script

Next steps

Additional resources
