Organizations in regulated industries such as financial services, government, defense, and healthcare restrict their sensitive workloads to isolated network environments with no access to the public internet. Until now, customers could restrict AWS Management Console access to authorized AWS accounts and corporate networks, but the console itself required internet connectivity. This was creating tension between operational convenience and network security controls.

We’re happy to announce that AWS Management Console Private Access is now generally available with support for virtual private clouds (VPCs) without internet connectivity. Organizations in regulated industries that restrict workloads to isolated network environments can now route all traffic for supported service consoles—including authentication flows, static assets (JavaScript, CSS, images), console-only APIs, and AWS service API calls—through AWS PrivateLink VPC endpoints, eliminating the need for an internet gateway, NAT gateway, or any route to the public internet. This capability is available in all AWS commercial Regions for a select set of supported service consoles.

In 2023, we launched AWS Management Console Private Access, which you can use to connect to the console by routing console, sign-in, and service API calls through VPC endpoints. However, accessing the console required internet connectivity for static assets and console-only APIs. This meant security teams faced a choice: allow internet connectivity to use the console or deny console access to operators working in network-isolated environments.

With this launch, AWS Management Console Private Access addresses two common scenarios:

• Console traffic over internet restricted networks: Traffic for supported service consoles now flows entirely through your VPC endpoints—no proxy allowlists to maintain, no TLS-intercepting proxies to operate, and no CLI-only workflows to accept as a compromise. The same path works seamlessly from Amazon WorkSpaces, Amazon Elastic Compute Cloud (Amazon EC2) instances, and on-premises networks connected through AWS Direct Connect or AWS Site-to-Site VPN. Combined with sign-in resource control policies (RCPs) and sign-in resource policies, you can ensure that console authentication only succeeds from expected networks—even if valid credentials are presented elsewhere, the session is denied. Teams that previously relied on restricted egress rules or manual domain allowlists now get full console access with the same network controls they already trust.
• Data-exfiltration prevention: Private Access enables you to restrict which AWS accounts and organizational identities can use the AWS Management Console from within your VPC. This prevents access from personal accounts and from accounts outside your organization. Attach a VPC endpoint policy with an aws:ResourceOrgID condition, and console actions are automatically scoped to resources inside your organization. Sign-in RCPs add a second layer by ensuring authentication only succeeds from networks within your perimeter. Together, these controls prevent supported service consoles from being used to access resources in accounts outside your organization—such as personal accounts—without requiring complex network-layer workarounds.

In this post, you will learn how AWS Management Console Private Access works in environments without internet connectivity, and how to layer access controls using VPC endpoint policies and sign-in resource control policies (RCPs) to strengthen your data perimeter.

Solution overview

AWS Management Console Private Access and sign-in resource control policies are a natural extension of the service control policies (SCPs), resource control policies, and VPC endpoint policies you already use for API traffic; now applied to the console session itself. The same data perimeter controls for identity, resource, and network that protect your programmatic access now protect interactive browser sessions too.

With this launch, Console Private Access routes browser traffic for supported service consoles through VPC endpoints, including:

• Authentication flows – Sign-in, credential exchange, and session token requests
• Static assets – JavaScript, CSS, and images that render the console UI
• Service console API calls – The backend requests made when users interact with service consoles

How traffic flows from a workload in a private VPC through the three Private Access endpoints, with no path to the public internet (shown in Figure 1):

1. The operator’s browser requests <region>.console.aws.amazon.com.
2. The corporate DNS forwarder forwards the query to an Amazon Route 53 Resolver inbound endpoint configured within the VPC, which forwards the traffic to the console VPC endpoint.
3. Browser traffic flows from on-premises through Direct Connect (or AWS Site-to-Site VPN) to the VPC, and the VPC endpoint routes traffic to the console service over the AWS private network.
4. The console service redirects to the SignIn endpoint <region>.signin.aws.amazon.com to establish a browser session.
5. The DNS now resolves to the SignIn VPC endpoint’s private IP addresses, and browser traffic flows to the SignIn service over the AWS private network.
6. After entering credentials, the SignIn service evaluates VPC endpoint policies, in addition to resource-based policies (RBPs) and RCPs, then redirects back to the console.
7. The console evaluates VPC endpoint policies, loads static content from the console API VPC endpoint, and enforces identity and resource restrictions when making calls to AWS service APIs.
8. Users can now access the AWS Management Console over Private Access.

Figure 1: Network isolation architecture

Deploy a pilot of AWS Management Console Private Access

This high-level walkthrough sets up AWS Management Console Private Access for a single AWS Region within one organizational unit (OU). We recommend rolling out incrementally; validate each step before you expand to additional Regions and OUs.

If you want to validate the mechanics of a Private Access deployment before you build out the full solution, the Getting started with a test environment guide walks you through a minimal configuration: a single VPC with the three Private Access endpoints and a permissive policy. This gives you a working setup to experiment with, independent of the deployment described in the rest of this post. To understand how sign-in policies can verify a user’s network location when they access the console, see Controlling console access with resource-based policies and resource control policies.

Prerequisites

You must have the following prerequisites:

• An AWS account that’s a member of an organization within AWS Organizations. The example RCP in Step 4 requires the management account access.
• A VPC in your chosen AWS Region with optional connectivity from your corporate network. This can be an AWS Direct Connect connection, an AWS Site-to-Site VPN, or workloads running directly in the VPC such as Amazon WorkSpaces or Amazon EC2 browsing instances.
• AWS CloudTrail enabled in the same Region to view ConsoleLogin events captured.
• Familiarity with AWS PrivateLink interface endpoints and AWS Identity and Access Management (IAM) policy evaluation.

Step 1: Baseline current console access

Before changing anything, use CloudTrail to map how your users access the console today. Search for eventName = ConsoleLogin over a representative window (we recommend 30 days) and review the sourceIPAddress, vpcEndpointId, and awsRegion fields. Identify which identity types are in use: root user, IAM user, SAML federation, and AWS IAM Identity Center. Decide which OU or account you will pilot with.

Note: A misconfigured sign-in policy can lock users out of the console. Avoid piloting in a production or shared account. Instead, use a dedicated test account and configure a break-glass principal (covered in Step 5) before enabling access enforcement.

Step 2: Create the Private Access VPC endpoints

In your chosen Region, create or identify a VPC to host the endpoints, then create three interface VPC endpoints in that VPC:

• com.amazonaws.<region>.console for the console.
• com.amazonaws.<region>.signin for AWS Sign-In.
• com.amazonaws.<region>.console-static for console-only APIs. This endpoint is required only if your VPC has no internet path.

Step 3: Configure private DNS for AWS Management Console Private Access

To use AWS Management Console Private Access, you must configure private DNS so that the console domains—.console.aws.amazon.com, .signin.aws.amazon.com, and the associated static-content domains—resolve to your interface endpoints’ network interfaces within your VPC.

• For workloads inside your VPC: If the workloads in your VPC use the default Amazon Route 53 Resolver, no additional DNS configuration is required. When you create each interface endpoint, enable the private DNS name option (set PrivateDnsEnabled = true). The public console domains will then resolve automatically to the endpoint network interfaces inside your VPC. If you use a custom DNS resolver or a private hosted zone, you must configure it explicitly to map the console domains to the endpoint addresses. See Working with private hosted zones for more information. For the complete list of domains and detailed DNS configuration steps, see the AWS Management Console Private Access required endpoints documentation.
• For workloads outside your VPC: For workloads that reach the endpoints from outside the VPC—such as corporate offices connecting over AWS Direct Connect or AWS Site-to-Site VPN—ensure that your corporate DNS resolver returns the endpoint addresses for these domains. See Simplify DNS management in a multi-account environment with Route 53 Resolver for more information.

Step 4: Verify private connectivity

Sign in to the console from a workload inside your VPC. The console should load normally. To confirm that traffic is routing through your VPC endpoints, look for the lock icon in the console navigation bar, shown in Figure 2.

Figure 2: Console Private Access

You can also verify in CloudTrail that recent ConsoleLogin events show the vpcEndpointId field populated with one of your endpoint IDs. Here’s an example CloudTrail ConsoleLogin event snippet showing the vpcEndpointId field:

{
  "eventVersion": "1.08",
  "userIdentity": {
    "type": "AssumedRole",
    "principalId": "AROA3XFRBF23EXAMPLE:john.doe",
    "arn": "arn:aws:sts::123456789012:assumed-role/Admin/john.doe",
    "accountId": "123456789012"
  },
  "eventTime": "2026-07-08T19:15:32Z",
  "eventSource": "signin.amazonaws.com",
  "eventName": "ConsoleLogin",
  "awsRegion": "us-east-1",
  "sourceIPAddress": "10.0.1.47",
  "userAgent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7)...",
  "requestParameters": null,
  "responseElements": {
    "ConsoleLogin": "Success"
  },
  "additionalEventData": {
    "LoginTo": "https://console.aws.amazon.com/console/home",
    "MobileVersion": "No",
    "MFAUsed": "Yes",
    "vpcEndpointId": "vpce-0abc123def456789a"
  },
  "eventID": "a1b2c3d4-5678-90ab-cdef-EXAMPLE11111",
  "eventType": "AwsConsoleSignIn",
  "recipientAccountId": "123456789012"
}

If the AWS Management Console doesn’t load, work through the following checks.

Private DNS is enabled on each interface endpoint (or your custom resolver returns the endpoint addresses)

When Private DNS is enabled, AWS automatically creates the DNS entries that resolve the service domains (such as console.aws.amazon.com) to the private IP addresses of your VPC endpoints. Without it, your browser still routes to the public AWS endpoints, bypassing your private access setup entirely.

1. Confirm that each endpoint shows PrivateDnsEnabled:

   aws ec2 describe-vpc-endpoints \
   --filters "Name=vpc-endpoint-type,Values=Interface" \
   --query "VpcEndpoints[].{Id:VpcEndpointId,Service:ServiceName,PrivateDns:PrivateDnsEnabled}" \
   --output table
   

2. Then, from within your VPC, verify that the domains resolve to private addresses:

   nslookup console.aws.amazon.com
   nslookup signin.aws.amazon.com
   
   # Should return a private IP (e.g., 10.x.x.x), not a public one
   

Each query should return a private IP address from your VPC CIDR range. If you use a custom DNS resolver instead of the Amazon-provided DNS, ensure your forwarding rules direct the AWS domain queries to the Route 53 Resolver inbound endpoints in your VPC.

The endpoint security groups allow HTTPS (TCP 443) from your workload subnets

Each VPC endpoint creates elastic network interfaces (ENIs) in your subnets, and these ENIs are governed by security groups. If those security groups don’t permit inbound HTTPS traffic from your workloads, the connection fails silently.

1. Identify the security groups attached to your endpoints:

   aws ec2 describe-vpc-endpoints --vpc-endpoint-ids vpce-0abc123def456789a \
     --query "VpcEndpoints[].Groups[].GroupId" --output text
   

2. Then verify that each security group allows inbound TCP 443 from your workload subnets:

   aws ec2 describe-security-groups --group-ids sg-xxxxxxxx \
     --query "SecurityGroups[].IpPermissions[?ToPort==\`443\`]" \
     --output json
   

For traffic from outside the VPC (Direct Connect or Site-to-Site VPN), corporate DNS returns the endpoint IPs and the route propagates correctly

If you access the console from an on-premises workstation connected over AWS Direct Connect or AWS Site-to-Site VPN, two additional conditions must be met.

1. Your corporate DNS must resolve the AWS domains to the VPC endpoint private IPs. From your on-premises machine, run:

   nslookup console.aws.amazon.com

   If this returns public AWS IPs, your corporate DNS isn’t forwarding queries through Route 53 Resolver. Configure conditional forwarding for the aws.amazon.com and amazonaws.com domains to your Resolver inbound endpoint IPs.

2. Second, network routes must propagate correctly. Ensure the route table associated with your endpoint subnets has propagated routes from your virtual private gateway (VGW) or transit gateway, so return traffic can reach your on-premises network. Verify this with:

   aws ec2 describe-route-tables \
     --filters "Name=association.subnet-id,Values=subnet-xxxxx" \
     --query "RouteTables[].PropagatingVgws"
   

A quick end-to-end validation: Run traceroute console.aws.amazon.com from your workstation and confirm the path uses private hops only—no traffic should traverse the public internet.

If the console loads but the lock icon is missing

If the console loads but the connection isn’t private (for example, the lock icon is missing), the browser is reaching the console over the public internet instead of through your VPC endpoints.

• Run nslookup console.aws.amazon.com from a workload inside the VPC. The result should be a private IP from your VPC CIDR range. A public IP means DNS is bypassing the endpoint, which usually happens because Private DNS has not been enabled on the interface endpoint (set PrivateDnsEnabled = true).
• For workloads outside the VPC, make sure your corporate DNS forwards the console domains into the VPC, for example, through an Amazon Route 53 Resolver inbound endpoint.

Step 5: Apply VPC endpoint policies

Attach an endpoint policy to the console and AWS Sign-In endpoints that limits access to identities in your organization. The static-content endpoint doesn’t support endpoint policies.

Begin with a permissive Allow * policy and confirm that traffic routes through the endpoints (you should see the vpcEndpointId field populated in CloudTrail console events). After confirming the routing, add restrictions to your VPC endpoint policy and observe the traffic.

A starter policy uses two condition keys: aws:PrincipalOrgID to restrict identities to your organization and aws:ResourceOrgID to restrict the resources the console can reach to your organization’s resources. The full reference, including additional condition keys and resource-restriction patterns, is in the AWS Management Console Private Access user guide.

For policies beyond the pilot, see Data perimeters on AWS. The data perimeter policy examples GitHub repository covers service-specific considerations for implementing data perimeters in your environment.

Step 6: Apply a Sign-In policy

Sign-In policies deny console authentication requests that don’t match your network or principal conditions. The policy is composed of a pre-authentication statement covering signin:Authenticate and a post-authentication statement covering signin:AuthorizeOAuth2Access and signin:CreateOAuth2Token. Include both statements.

For your pilot, deploy the policy as an RCP from your AWS Organizations management account. When enabled, the RCP applies to all accounts in your organization, so we recommend piloting in a dedicated test organization before rolling it out broadly. Activate enforcement by calling the signin:PutConsoleAuthorizationConfiguration API for the organization in the us-east-1 Region (AWS Sign-In replicates policies globally from there). Resource permission statements have no effect until console authorization is enabled.

Important: Configure at least one excluded principal as a break-glass path before you enable the RCP. The recommended principal is a dedicated IAM role.

1. Write the permission statements that define the network conditions:
   Example – Restrict access to corporate VPC:

   aws signin put-resource-permission-statement \
     --source-vpc vpc-0abc123def456789 \
     --requested-region us-west-2 \
     --excluded-principal "arn:aws:iam::123456789012:user/EmergencyAdmin" \
     --region us-east-1
   

   Example – Restrict access to specific IP range:

   aws signin put-resource-permission-statement \
     --source-ip "IP_ADDRESS" \
     --excluded-principal "arn:aws:iam::123456789012:role/BreakGlassRole" \
     --region us-east-1
   

2. Enable console authorization for the organization to start enforcing the policy.

   aws signin put-console-authorization-configuration \
     --target-id <your-target-id> \
     --region us-east-1
   

3. Review the consolidated policy that’s now in effect: 

   aws signin get-resource-policy --region us-east-1
   

For policy examples, the AWS Command Line Interface (AWS CLI) reference, and the lockout-recovery procedure, see the sign-in RBP blog post and the Controlling console access with resource-based policies documentation. The same documentation also covers the per-account alternative, which uses an RBP attached to a single account instead of an organization-wide RCP.

Step 7: Add a service VPC endpoint

So far, the console shell loads, the lock icon appears, and your Sign-In policy lets approved identities through. If you sign in to a service console such as the AWS Key Management Service (AWS KMS) console, the page might fail to load resources or hang. The Private Access endpoints carry the console shell, not the service API calls that the console makes on your behalf. In a VPC without an internet gateway, those calls have nowhere to go.

Add a VPC endpoint for the service itself. For the pilot, create an AWS KMS interface endpoint (com.amazonaws.<region>.kms) in the same VPC, with Private DNS enabled. Open the AWS KMS console from inside the VPC and confirm the list of keys loads. Repeat for each service your users need on day one. Please note that a single service console often calls more than one AWS service API. If a console loads but parts of the page show errors or stay empty, the most common cause is a missing endpoint for one of the services it depends on.

The current list of services that support PrivateLink is in the AWS PrivateLink documentation. Service consoles whose services don’t support PrivateLink will not work in a no-internet VPC and need to be handled separately.

Step 8: Hide Regions and services you haven’t configured (optional)

Console links to a service or Region that you don’t have endpoints for will fail inside your VPC. To prevent users from navigating to broken pages, use User Experience Customization (UXC) to hide Regions and services that aren’t part of your Private Access deployment. UXC is configured at the account level and applies to navigation, search results, and service-selection drop-downs.

Step 9: Validate, then expand

After applying the endpoint policies and the Sign-In RCP to one pilot account:

1. Sign in from inside the corporate network. The session should succeed.
2. Sign in from outside the corporate network. The session should be denied at the Sign-In step, before reaching the console.
3. In CloudTrail, confirm ConsoleLogin events show vpcEndpointId populated for traffic from inside the network.
4. For unexpected denials, look in CloudTrail for ConsoleLogin events with the error message Authorization denied because of a resource-based policy or Authorization denied because of a resource control policy to identify which statement was responsible.

Considerations

A few items worth mentioning before you commit to this design:

• AWS IAM Identity Center: IAM Identity Center sign-in support isn’t yet available through a VPC endpoint. Initial single sign-on (SSO) authentication must still transit over the internet.
• Programmatic access: Sign-In RBPs and RCPs gate interactive console sign-in. AWS SDK and AWS CLI requests signed with SigV4 aren’t affected. This is also your recovery path: a principal with signin:DeleteConsoleAuthorizationConfiguration permission can disable enforcement programmatically if console authorization is misconfigured.
• Apps integrated with AWS Sign-In: Sign-In policies also apply to Amazon Connect, Amazon WorkSpaces, Amazon QuickSight, AWS Health Dashboard, Amazon AppStream 2.0, and Amazon Lightsail when those applications use AWS Sign-In to authenticate.
• AWS Management Console Private Access is available in all commercial AWS Regions but supports only a subset of AWS service consoles. See Supported AWS Regions, service consoles, and features in Private Access documentation for more information.
• For services that aren’t supported, you can still navigate to other consoles, but will require internet connectivity for the unsupported service consoles and console-only APIs.
• Costs: You pay regular AWS PrivateLink endpoint pricing and data processing for each endpoint and each Region you deploy in. The three Private Access endpoints (console, signin, and console-static) plus the service endpoints you already use are the relevant line items.

Conclusion

In this post, we showed you how to extend the AWS data perimeter framework to the AWS Management Console. You routed console traffic through VPC endpoints with AWS Management Console Private Access, restricted console sign-in by network and organization with Sign-In RBPs and RCPs, and configured the console to operate in a VPC without an internet gateway. The four control objectives that you already enforce for API traffic now also apply to the console.

To get started, see the AWS Management Console Private Access documentation. For deployment patterns and Region-by-Region considerations, see the AWS Management Console Private Access reference architectures. For background on the broader pattern, see Establishing a data perimeter on AWS.

If you have feedback about this post, submit comments in the Comments section below. If you have questions about this post, start a new thread on the IAM forum on AWS re:Post or contact AWS Support.

When an administrator introduces a rule change in AWS Network Firewall and network connectivity is disrupted, pinpointing the cause requires inspecting multiple points in the traffic path. The firewall gives you stateless and stateful rule engines, domain rules, and routing to the firewall endpoint inside your Amazon Virtual Private Cloud (Amazon VPC). A network drop looks the same from the workload no matter where it started. Isolating the cause means correlating the alert and flow logs with the firewall configuration, route tables, and recent API calls in AWS CloudTrail that might have changed them. That manual correlation is exactly where AWS DevOps Agent helps, accelerating root cause analysis so you can restore connectivity in minutes instead of hours.

AWS DevOps Agent does that correlation for you. As your always-available operations teammate, it resolves and proactively prevents operational issues across AWS, multicloud, and on-premises environments. When an Amazon CloudWatch alarm triggers, it reaches the agent through a webhook. The agent then reads the firewall configuration and logs through AWS APIs, ties the drop to recent API activity, and returns a root cause with a mitigation plan you review before you apply it.

This post connects CloudWatch monitoring to DevOps Agent. It walks through three Network Firewall failures from end to end. The first is a domain deny list blocking a legitimate endpoint. The second is a stateless rule priority misconfiguration. The third is an asymmetric cross Availability Zone (AZ) routing drop. Each maps to a different layer, so each leads down a different investigation path. An AWS Cloud Development Kit (AWS CDK) app deploys the whole environment in your own account so you can reproduce each failure and follow along.

As part of this blog post, we provide a CDK stack that deploys both the AWS DevOps Agent Space and a sample workload used to walk through three separate troubleshooting scenarios. A single t3.micro instance in a protected subnet checks its connectivity to a test endpoint on a continuous loop and publishes results to CloudWatch. Traffic takes the internet egress path through Network Firewall, the NAT gateway, and the internet gateway, so the firewall can intercept or drop it. After completing the walkthrough, you can apply the same troubleshooting techniques with DevOps Agent against your own Network Firewall deployments.

The test endpoint runs in a separate VPC deployed by the same CDK app. It serves HTTPS on port 443 and TCP on port 9142, giving each scenario a different protocol layer to exercise: Scenario 1 targets a TLS connection on 443 (matched by Server Name Indication), Scenario 2 targets a TCP connection on 9142, and Scenario 3 exercises the whole egress path.

A live status page shows one card per scenario plus the network topology. The whole stack deploys from a single CDK app across two Availability Zones, each with a firewall endpoint and NAT gateway, which is what makes Scenario 3 possible.

As shown in the following figure, the egress data path runs from the workload through Network Firewall and the NAT and internet gateways to the test endpoint. The alarm pipeline runs from CloudWatch through Amazon Simple Notification Service (Amazon SNS) and the webhook AWS Lambda function to DevOps Agent.

Figure 1: The sample workload

To use this with your own workload, you need a CloudWatch alarm that detects the connectivity problem and the webhook pipeline (SNS topic and Lambda function) that delivers it to DevOps Agent. The agent reads your firewall configuration, logs, and CloudTrail through AWS APIs, so no additional instrumentation is needed on the firewall side.

To follow along with this post, you need:

• An AWS account with permissions to deploy Amazon VPC, Network Firewall, Amazon Elastic Compute Cloud (Amazon EC2), CloudWatch, Amazon SNS, Lambda, Amazon CloudFront, and AWS Identity and Access Management (IAM) resources
• Access to AWS DevOps Agent, with permission to configure its webhook
• Node.js 18 or later and npm installed
• AWS Command Line Interface (AWS CLI) 2.x configured with credentials
• AWS CDK 2.x is required. You can use it through the project’s npx dependency, or install it globally:
  • npm install -g aws-cdk

Clone the project and deploy it into us-east-1 with one command (set awsRegion to use another AWS Region).

git clone https://github.com/aws-samples/sample-accelerating-aws-network-firewall-troubleshooting-with-aws-devops-agent.git
cd sample-accelerating-aws-network-firewall-troubleshooting-with-aws-devops-agent
bash scripts/deploy.sh

The script checks prerequisites, installs dependencies, compiles and tests, and bootstraps the CDK if needed. It then deploys all the stacks from a clean baseline and prints the outputs, including the status-page URL and sign-in details.

1. Open the status-page link (an https://<random-id>.cloudfront.net address).
2. Sign in using the username and password provided from the CDK output and confirm all three cards show the green Healthy status.
3. Keep the page open while you run the scenarios.

To connect AWS DevOps Agent to the alarm pipeline

1. In the AWS DevOps Agent console, open the nf-devops-agent-space Agent Space created by the CDK deployment.
2. Configure the DevOps Agent webhook and download the CSV file with the webhook URL and signing secret.
3. On the status page, choose Configure webhook, paste the URL and signing secret, and save. The page writes them to the nf-devops-agent-webhook-credentials AWS Secrets Manager secret, so there is no AWS CLI or console step. Until you set it, the bridge Lambda function sees a placeholder and skips delivery.
4. Verify the path before you run a scenario. In the Lambda console, open nf-devops-agent-webhook and use the Test tab with this event.

   {
     "Records": [
       {
         "Sns": {
           "Message": "{\"AlarmName\":\"TEST-webhook-verification\",\"AlarmDescription\":\"[TEST] Webhook integration test - not a real alarm.\",\"NewStateValue\":\"ALARM\",\"NewStateReason\":\"[TEST] Manual webhook connectivity test. Safe to ignore.\",\"Region\":\"us-east-1\"}"
         }
       }
     ]
   }

5. A 200 response confirms the path, and a test investigation appears in the DevOps Agent Operator Web App view.

Every scenario reaches DevOps Agent the same way. A CloudWatch alarm moves to ALARM and notifies the SNS topic. Amazon SNS invokes a Lambda function. The function reads the webhook URL and signing secret from Secrets Manager, signs an alarm payload, and POSTs it to the DevOps Agent webhook (as shown in Figure 1). Amazon SNS also provides delivery retries, fan-out to other subscribers, and cross-account publishing.

• Prebuilt Network Firewall metric (Scenario 1) – Alarm-1 watches the DroppedPackets metric, summed across the stateful streams, and triggers when drops rise above a baseline threshold. This requires no workload or custom metric and works on an already-deployed firewall. However, it only tells you that the firewall is dropping packets, not which rule is responsible.
• Application health metric (Scenarios 2 and 3) – Alarm-2 and Alarm-3 watch a custom metric from a connectivity check. Use this for an alarm tied to user-facing impact or to tell one traffic path from another, which requires running a component that emits the metric.

Work through each of the scenarios one at a time, following the same cycle. Interrupt network connectivity, watch the alarm trigger, let DevOps Agent investigate, apply the recommended fix, and confirm recovery before moving on.

The status-page cards follow the live CloudWatch alarm state. A card shows a green dot and the word Healthy when its alarm is clear, and a red dot and the word DROPPED when its alarm triggers. In the DROPPED state the card also adds a Condition: line describing what’s being dropped, which isn’t shown when the card is healthy. Network Firewall applies changes to new flows, so a change shows within a minute or two. Recovery comes from the mitigation DevOps Agent recommends, which you review and apply.

At baseline, the rg-domain Suricata domain rule group denies only an unused placeholder, so the test endpoint stays reachable. The rule group inspects the TLS Server Name Indication (SNI) on each outbound connection and drops any that matches a denied domain. The exact rule syntax and console steps follow.

To add the domain deny rule

1. Go to the Amazon VPC console.
2. In the navigation pane, under Network Firewall, choose Network Firewall rule groups.
3. Choose the rg-domain rule group to open its details page.
4. In the Rules section, choose Edit.
5. The rules box already contains two baseline placeholder rules (they match blocked.placeholder.invalid, so nothing real is denied). Leave those in place. Find the <app-endpoint-dns> value for Scenario 1 in the deployment script output (a Nework Load Balancer (NLB) DNS name such as NfTest-AppNl-a1b2C3dEf4G5-1234abcd5678efgh.elb.us-east-1.amazonaws.com). On a new line below the existing rules, add a drop rule that matches that DNS name on the TLS SNI, then choose Save.

   drop tls $HOME_NET any -> $EXTERNAL_NET any (ssl_state:client_hello; tls.sni; content:"<app-endpoint-dns>"; startswith; nocase; endswith; msg:"S1 domain denylist"; flow:to_server, established; sid:2000002; rev:1;)

6. After saving, the rules box holds all three lines. The two placeholders remain, plus the new drop rule for the endpoint DNS name (note the distinct sid 2000002).

Figure 2: Scenario 1 – Firewall rule change blocking the connection

What happens. The workload’s HTTPS check to the test endpoint times out, the “AWS/NetworkFirewall DroppedPackets metric climbs above baseline, and Alarm-1 moves to ALARM. The Scenario 1 card reads DROPPED (with the condition Firewall dropping the monitored domain on its allow/deny rules), while the Scenario 2 and Scenario 3 cards stay Healthy (Figure 3). On the topology, the alarm pipeline from CloudWatch through Amazon SNS and Lambda to DevOps Agent and the workload-to-firewall inspect lines both turn amber, which the legend defines as collateral / alarm active, because the packets are now dropped at the firewall. To demonstrate the resulting failure, the HTTPS · SNI line from the internet gateway to the test endpoint is shown in red, which the legend defines as dropped (root cause).

Figure 3: Scenario 1 active – Traffic blocked at the firewall

Let DevOps Agent investigate. The agent runs several lines of investigation in parallel and correlates them:

1. Reads the DroppedPackets metric and correlates the spike with a simultaneous drop in passed packets, confirming the firewall is actively blocking traffic.
2. Reads the ALERT log and finds the workload’s TLS connections to the test endpoint blocked by the S1 domain denylist rule.
3. Compares the current state against a baseline window, where the same endpoint was reachable with no alerts, which shows the block is new.
4. Searches CloudTrail and surfaces the UpdateRuleGroup call that added the deny rule, identifying the user, role, and timestamp approximately one minute before the drops began.
5. Reports the root cause as that manual rule-group change. Recommends removing the deny entry or adding an allow exception and enabling FirewallPolicyChangeProtection to prevent unauthorized changes.
6. Presents this as a plan you review and apply, not an automatic change.

In the DevOps Agent Operator Web App view, the agent first restates the Alarm-1 trigger and confirms the firewall is dropping packets above the threshold (Figure 4).

Figure 4: Scenario 1 – The symptom

Next, the agent identifies the root cause: a manual update to the rg-domain rule group that added a domain deny rule (SID 2000002) shortly before the alarm fired, blocking TLS connections to the ELB endpoint (Figure 5).

Figure 5: Scenario 1 – The root cause

Finally, the agent presents a mitigation plan, recommending you remove the problematic deny rule (SID 2000002) to restore connectivity (Figure 6).

Figure 6: Scenario 1 – The mitigation plan

Note: In a real-world environment, this type of rule typically exists for a reason. Before removing it, verify whether it was intentional but scoped too broadly. If so, refine the rule to block only unauthorized endpoints rather than removing it entirely.

Confirm recovery. Apply the change the agent recommends. After the deny entry is gone, DroppedPackets falls back to baseline, Alarm-1 clears, and the card returns to green. Move on to Scenario 2.

At baseline, the rg-stateless-priority stateless rule group keeps the allow rule at priority 100 and the drop rule at 200 for the test class, TCP destination port 9142. The workload opens a TCP connection to the test endpoint on this port. Lower priority numbers evaluate first, so the allow rule wins. This scenario uses port 9142 instead of 443 to demonstrate a stateless rule, which matches on the packet’s 5-tuple (protocol, ports, addresses) rather than application content.

Introduce the change. Invert the two rule priorities so the drop rule evaluates before the allow rule. This is the kind of change a rushed rule edit can introduce.

To invert the stateless rule priorities

1. Go to the Amazon VPC console.
2. In the navigation pane, under Network Firewall, choose Network Firewall rule groups.
3. Choose the rg-stateless-priority rule group to open its details page.
4. In the Rules section, choose Edit.
5. Raise the (Action: Pass) rule’s priority number so it sits after the (Action: Drop) rule, then choose Save. For example, change the (Action: Pass) rule from 100 to 300 (any number higher than the drop rule’s 200 works). You only need to move one rule, and using 300 avoids a clash with the drop rule that already sits at 200. Network Firewall evaluates the lowest priority number first, so the (Action: Drop) rule at 200 now wins for this traffic class, ahead of the (Action: Pass) rule at 300.

Figure 7: Scenario 2 – Rule priority change blocking the traffic class

What happens. The drop rule now wins, the TCP connection to the test endpoint on port 9142 times out, the StatelessRuleFailures metric climbs above baseline, and Alarm-2 moves to ALARM. The Scenario 2 card reads DROPPED (with the condition Stateless rules dropping the monitored traffic class), while the Scenario 1 and Scenario 3 cards stay Healthy (Figure 8). On the topology, the alarm pipeline from CloudWatch through Amazon SNS and Lambda to DevOps Agent and the workload-to-firewall inspect lines both turn amber, which the legend defines as collateral / alarm active, because the packets are now dropped at the firewall. To demonstrate the resulting failure, the TLS :9142 line from the internet gateway to the test endpoint is shown in red, which the legend defines as dropped (root cause).

Figure 8: Scenario 2 active

Let DevOps Agent investigate. A stateless drop happens before traffic reaches the stateful inspection engine, so it produces no ALERT log entries. The agent turns to configuration and flow logs instead:

1. Reads the stateless rule group state and finds the drop rule at the lower priority number, ahead of the pass rule, so the drop evaluates first.
2. Reads the flow logs and sees passed packets drop to zero within a minute of the change.
3. Searches CloudTrail and surfaces the UpdateRuleGroup call that inverted the priorities, identifying the user, role, and timestamp about a minute before the alarm.
4. Reports the root cause as that priority inversion. Recommends removing the redundant drop rule and managing the rule group through infrastructure-as-code (IaC) to prevent manual misconfigurations.
5. Presents this as a plan you review and apply, not an automatic change.

In the DevOps Agent Operator Web App view, the agent first restates the Alarm-2 trigger and confirms that a workload connectivity health check is failing because the firewall’s stateless rules are dropping egress (Figure 9).

Figure 9: Scenario 2 – The symptom

Next, the agent identifies the root cause, using the rule-group state and CloudTrail to pinpoint the conflicting DROP/PASS rules, where the new DROP rule’s lower priority number makes it match first (Figure 10).

Figure 10: Scenario 2 – The root cause

Finally, the agent presents a mitigation plan, recommending you remove the conflicting DROP rule at priority 200 to restore traffic flow (Figure 11).

Figure 11: Scenario 2 – The mitigation plan

Confirm recovery. Apply the change the agent recommends. After the allow rule is ahead of the drop rule again, Alarm-2 clears and the card returns to green. Move on to Scenario 3.

At baseline, the protected subnet in each Availability Zone routes its egress through the firewall endpoint in that same Availability Zone , and the matching return route uses that same endpoint. One endpoint sees both directions of the flow, so the stateful engine completes the handshake. The workload runs in the protected subnet in us-east-1a (CIDR 10.0.4.0/24), so at baseline its egress and its return both use the us-east-1a firewall endpoint.

Introduce the change. Make the flow asymmetric by sending egress out one Availability Zone endpoint while the return comes back through the other. This takes two route edits, and both are required. With only the first edit the flow can still complete, so the alarm will not trigger until both are saved. It makes no firewall-policy change, mirroring a real multi-Availability-Zone routing mistake.

To create asymmetric cross Availability Zone routing

1. Go to the Amazon VPC console and choose Route tables in the navigation pane.
2. Flip the egress. Select the NfNetworkStack/SampleVpc/protectedSubnet1 route table (the us-east-1a protected subnet, where the workload runs). On the Routes tab, choose Edit routes. Its 0.0.0.0/0 route currently targets the us-east-1a firewall endpoint. For the target, choose Gateway Load Balancer Endpoint and select the us-east-1b firewall endpoint, then choose Save changes.
3. Move the return. Select the NfNetworkStack/SampleVpc/publicSubnet2 route table (the us-east-1b public subnet, where egress now exits). Choose Edit routes, then Add route. For the destination enter the workload CIDR 10.0.4.0/24. For the target, choose Gateway Load Balancer Endpoint and select the us-east-1a firewall endpoint. Choose Save changes.

After both edits, a flow’s egress leaves through the us-east-1b endpoint while its return is directed to the us-east-1a endpoint. Neither endpoint sees the whole flow.

Figure 12: Scenario 3 routing change breaking the flow’s symmetry

What happens. A new connection leaves through one endpoint. Its return arrives at the other endpoint, which never saw the connection open, so the handshake fails. Unlike Scenarios 1 and 2, this affects the whole subnet, so all egress stops and Alarm-2 and Alarm-3 both move to ALARM. The AWS/NetworkFirewall DroppedPackets alarm (Alarm-1) stays quiet because no endpoint is making a drop decision. The flow is lost to asymmetric routing rather than counted as a firewall drop. This is why monitoring application connectivity matters. A routing fault is invisible to the firewall’s own drop counter. On the status page, the Scenario 2 card reads DROPPED (with the condition “Stateless rules dropping the monitored traffic class”) and the Scenario 3 card reads DROPPED (with the condition Return traffic dropped by asymmetric cross-Availability-Zone routing), while the Scenario 1 card stays Healthy (Figure 13). On the topology, the alarm pipeline from CloudWatch through Amazon SNS and Lambda to DevOps Agent and the workload-to-firewall inspect lines both turn amber, which the legend defines as collateral / alarm active, while the egress path from the firewall through the NAT gateway and the TLS :9142 and HTTPS · routing lines to the test endpoint turn red, which the legend defines as dropped (root cause).

Figure 13: Scenario 3 – The status page during a path-wide outage

Let DevOps Agent investigate. Both Alarm-2 and Alarm-3 fire in the same datapoint. DevOps Agent recognizes them as linked and merges them into a single investigation:

1. Reads the flow logs and sees bidirectional TLS connections stop abruptly, with only one-way traffic remaining and no flows reaching the established state.
2. Reads the firewall metrics and sees received and passed packets shift from one Availability Zone to the other at the moment of the change.
3. Calls DescribeRouteTables and finds the egress route pointing at one Availability Zone firewall endpoint while the return route points at the other.
4. Searches CloudTrail and surfaces the ReplaceRoute and CreateRoute calls by the same user, about a minute before both alarms fired.
5. Reports the root cause as that asymmetric routing change. Recommends restoring symmetric same-Availability-Zone routing so egress and return traverse the same endpoint.
6. Presents this as a plan you review and apply, not an automatic change.

A mitigation plan is a recommendation you review, not an automatic change, and the right fix depends on the intended design. Restoring symmetric routing can mean sending the workload subnet’s egress back through its own-Availability-Zone firewall endpoint (this sample’s architecture) or, in a design that doesn’t inspect this path, back through a NAT gateway. The agent infers a plausible target from what it can observe, so review the specific route it proposes against your intended topology before you apply it. (Connecting your pipeline or infrastructure-as-code, covered in the next section, lets the agent recommend the target that matches your design.)

In the DevOps Agent Operator Web App view, the agent restates the Alarm-3 (AsymmetricFlowFailures) trigger and confirms the workload’s egress to a monitored endpoint is being blocked by the Network Firewall (Figure 14).

Figure 14: Scenario 3 – The symptom

Next, the agent identifies the root cause: manual route table changes that created cross-AZ asymmetric routing through the network firewall, breaking its symmetric routing requirement (Figure 15)

Figure 15: Scenario 3 – The root cause

Finally, the agent presents a mitigation plan, recommending you restore symmetric routing by pointing protectedSubnet1‘s default route back to the same Availability Zone firewall endpoint, so one endpoint sees both directions of the flow again (Figure 16).

Figure 16: Scenario 3 – The mitigation plan

Confirm recovery. Apply the change the agent recommends, after checking the route target matches your intended design. After the workload subnet’s egress and return use the same Availability Zone firewall endpoint again, the control probe recovers, the alarms clear, and every card returns to green.

In production a single change can trigger several alarms at the same time, as Scenario 3 shows. DevOps Agent links related investigations and works them as one, so you review a single root cause. You can validate the linked findings or unlink an alarm to investigate it independently. If you would rather collapse alarms before they reach the agent, you can add correlation logic in the bridge Lambda function, buffering and grouping by firewall. You can also add email, Amazon Simple Queue Service (Amazon SQS), or HTTP subscribers to the SNS topic, or add the webhook Lambda function to a topic you already run. DevOps Agent produces a mitigation plan but does not change your environment on its own.

You can also give the agent more to work with. DevOps Agent connects to source repositories and CI/CD pipelines, integrating with GitHub (including GitHub Enterprise Server and GitLab Self-Managed through a private connection). It can associate AWS resources with deployments of AWS CloudFormation, AWS CDK, Amazon Elastic Container Registry (Amazon ECR) images, and Terraform. With deployed configuration and recent deployment events in view, the agent correlates the disruption against the change that introduced it and recommends a fix matching your intended design. For this sample, that means recommending the workload subnet’s own Availability Zone firewall endpoint rather than a generic symmetric path.

DevOps Agent also supports proactive incident prevention. It analyzes patterns across past investigations and delivers recommendations to prevent similar issues from recurring, including governance recommendations that strengthen deployment processes and pipeline controls. For Network Firewall rule changes, this means the agent can recommend guardrails for your CI/CD pipeline based on the classes of misconfigurations it has already resolved. You can access these recommendations through the Improvements page in the DevOps Agent Operator Web App.

Clean up the environment with one command.

bash scripts/destroy.sh

It reverts any active scenario, runs cdk destroy for all stacks, and sweeps for stragglers by the Project = nf-devops-agent tag. The main cost drivers are the two Network Firewall endpoints, the NAT gateways (one in the main VPC for each Availability Zone, one in the test-endpoint VPC), and the test endpoint’s load balancers. Each of these bills at an hourly rate for as long as it’s provisioned, whether or not traffic is flowing, so a stack left running continues to accrue charges around the clock even while idle. Running the scenarios and tearing the stack down the same day limits the cost to a few active hours rather than days of idle hourly charges.

In this post, we showed you how AWS DevOps Agent accelerates troubleshooting for three common network firewall connectivity issues. The first was a domain deny list. The second was a stateless priority inversion. The third was an asymmetric cross-AZ routing drop. For each one, DevOps Agent investigated the drop and returned a root cause with a mitigation plan you approve before applying. The first scenario triggered on a prebuilt Network Firewall metric, and the other two on application health metrics. That shows both ways to alarm on a firewall problem through one pipeline.

The pattern isn’t specific to Network Firewall. The same flow fits any service that emits CloudWatch metrics and logs, such as AWS WAF, security groups, and network ACLs. Clone the sample repository to explore the solution, then apply what you learn to your own firewall, application, and alarms. For more details, see the AWS Network Firewall Developer Guide and the AWS Network Firewall pricing page. Start with the Getting Started with AWS DevOps Agent guide to connect your first webhook.

Amazon Web Services (AWS) is pleased to announce that the Spring 2026 System and Organization Controls (SOC) 1, 2, and 3 reports are now available. The reports cover 188 services over the 12-month period from April 1, 2025–March 31, 2026, giving customers a full year of assurance. These reports demonstrate our continuous commitment to adhering to the heightened expectations of cloud service providers.

Customers can download the Spring 2026 SOC 1 and 2 reports through AWS Artifact, a self-service portal for on-demand access to AWS compliance reports. Sign in to AWS Artifact in the AWS Management Console, or learn more at Getting Started with AWS Artifact. The SOC 3 report can be found on the AWS SOC Compliance Page and AWS Artifact.

AWS strives to continuously bring services into the scope of its compliance programs to help customers meet their architectural and regulatory needs. You can view the current list of services in scope on our Services in Scope page. As an AWS customer, you can reach out to your AWS account team if you have any questions or feedback about SOC compliance.

To learn more about AWS compliance and security programs, see AWS Compliance Programs.

If you have feedback about this post, submit comments in the Comments section below.

AWS Network Firewall now supports native attachment to AWS Transit Gateway. Customers commonly use Transit Gateway to route traffic from Amazon Virtual Private Cloud (Amazon VPC) networks to a centralized inspection VPC (a VPC dedicated to hosting firewall endpoints for traffic inspection) where their network firewall endpoints are deployed. This centralized deployment model reduces the need to have Network Firewall endpoints in each VPC, optimizing costs and providing a centralized point of network security control.

Customers deploying Network Firewall in a centralized deployment model using Transit Gateway have traditionally set up a dedicated inspection VPC with firewall subnets and managed the associated routing to direct traffic through the firewall. With native attachment, Network Firewall attaches directly to Transit Gateway, eliminating the need for the inspection VPC and enabling capabilities such as flexible cost allocation through Transit Gateway metering policies.

In this post, we explain what a Transit Gateway-attached network firewall is, the technical capabilities it unlocks, reasons to migrate to it, and how to perform the migration. For detailed step-by-step guidance on how to perform the migration using Terraform, AWS CloudFormation, or manually in the AWS Management Console, see the accompanying migration guide repository.

A Transit Gateway-attached network firewall simplifies your network architecture by eliminating the need for a dedicated inspection VPC. Instead of creating an inspection VPC with firewall subnets and configuring the associated routing, you create your network firewall and specify which Transit Gateway instance you want to attach it to. AWS deploys the firewall endpoints into an AWS-managed VPC on your behalf. You don’t own or manage that VPC. From your perspective, the firewall appears as a Transit Gateway network function attachment that you route traffic to, similar to other Transit Gateway attachments.

You might want to migrate to a Transit Gateway-attached network firewall for the following reasons:

• Access to flexible cost allocation: With native attachment, you can use Transit Gateway metering policies to charge back account owners for traffic they send through the centralized firewall. Flexible cost allocation for Network Firewall traffic over a Transit Gateway is only available with a Transit Gateway-attached firewall. Without native attachment, you can only allocate Transit Gateway data processing charges, not the Network Firewall charges.
• Reduced architectural complexity: You can eliminate the inspection VPC, leaving one less VPC to manage along with its associated routing tables and subnets.

Before migrating to a Transit Gateway-attached network firewall, gather the following information and keep these key considerations in mind.

When you create your new Transit Gateway-attached network firewall, you will need:

• Transit Gateway ID: The ID of the Transit Gateway instance you will attach your network firewall to.
• Logging configuration: Create a new logging configuration (such as new Amazon CloudWatch log groups) for the new firewall. During migration, you will be running both firewalls simultaneously. Keeping the logs separate simplifies monitoring and troubleshooting each firewall during the migration period. After migration is complete, you can point the new firewall to your existing logging destinations.
• Firewall policy: Create a new firewall policy for the new firewall rather than reusing your existing one. During the migration period, a separate policy lets you make changes to the new firewall’s policy without affecting the existing firewall while both are running simultaneously. After migration is complete, you can attach your existing production policy to the new firewall.

There are some important considerations to address while planning for this change.

• Transit Gateway encryption: Check if you’re using Transit Gateway encryption support. If encryption is enabled and required for your security posture, native attachment to Network Firewall doesn’t currently support this capability. You will need to continue using your current firewall configuration.
• NAT gateway Elastic IPs: If you need to maintain the same public IPs (for example, for partner allowlisting), plan for this during migration. For more information, see the Preserving your NAT gateway Elastic IPs during migration section later in this post.
• Maintenance window: Plan to perform this migration during a dedicated maintenance window. Brief network outages will occur during parts of the process, such as when swapping Transit Gateway route table associations and replacing NAT gateways.

Leave your existing Network Firewall setup unchanged while setting up the new Transit Gateway-attached firewall. With this approach, you can minimize potential downtime and test the new configuration before migrating production traffic.

The migration process varies depending on your current architecture. The following sections walk through the two most common centralized Network Firewall architectures and the high-level migration process for each. For detailed step-by-step guidance on how to perform the migration using Terraform, CloudFormation, or manually in the console, see the migration guide repository.

In this architecture, shown in the following diagram, you have a dedicated inspection VPC with your network firewall endpoints, and a separate dedicated egress VPC with your NAT gateways.

Figure 1: Centralized egress traffic inspection with Network Firewall and Transit Gateway, with inspection and egress separated into two VPCs.

The high-level migration process for this architecture is:

1. Deploy a new egress VPC with a temporary NAT gateway. Creating a new VPC lets you leave the existing deployment unchanged while working on the migration.
2. Create your new network firewall with native attachment to your Transit Gateway.
3. Configure three new Transit Gateway route tables to define the traffic path through the new firewall: an inspection route table (associated with the new firewall), an egress route table (associated with the new egress VPC), and a temporary migrated spoke route table (for testing individual spoke VPCs on the new path).
4. Test the new firewall by moving a single spoke VPC to the new path. Verify connectivity and confirm the firewall is inspecting traffic by checking the alert logs for layer 7 (application layer) details. Layer 7 information in the alert logs indicates the firewall is seeing both directions of the traffic flow. If asymmetric routing were occurring, the firewall would only see one direction and would not be able to perform application-layer inspection, so the presence of layer 7 details confirms traffic is flowing symmetrically through the new firewall.
5. Migrate the remaining spoke VPCs. You can migrate VPCs incrementally, or when you’re confident in the new firewall deployment, update the default route in your existing spoke route table to point to the new Network Firewall network function attachment, which moves all remaining spokes that share that route table at once.
6. Optionally, preserve your original NAT gateway Elastic IPs by re-routing traffic back to your existing egress VPC (see Preserving your NAT gateway Elastic IPs during migration).
7. Decommission old resources after you’ve verified that traffic is flowing correctly. Which VPCs you remove depends on whether you preserved your original EIPs (see Preserving your NAT gateway Elastic IPs during migration).

Figure 2: Post-migration architecture for Architecture 1, with the inspection VPC eliminated and traffic flowing through the Transit Gateway-attached Network Firewall to a dedicated egress VPC.

For the complete walkthrough of how to perform this migration:

• Terraform migration guide
• CloudFormation migration guide
• Manual console migration guide

In this architecture, shown in the following diagram, you have a single VPC that contains both your network firewall endpoints and your NAT gateways.

Figure 3: Centralized egress traffic inspection with Network Firewall and Transit Gateway, with inspection and egress combined in one VPC.

The migration process for this architecture follows the same high-level steps as Architecture 1.

1. Deploy a new dedicated egress VPC with a temporary NAT gateway. Creating a new VPC lets you leave the existing deployment unchanged while working on the migration.
2. Create your new network firewall with native attachment to your Transit Gateway.
3. Configure three new Transit Gateway route tables to define the traffic path through the new firewall: an inspection route table, an egress route table, and a temporary migrated spoke route table.
4. Test the new firewall by moving a single spoke VPC to the new path. Verify connectivity and confirm the firewall is inspecting traffic by checking the alert logs for layer 7 (application layer) details. Layer 7 information in the alert logs indicates the firewall is seeing both directions of the traffic flow. If asymmetric routing were occurring, the firewall would only see one direction and would not be able to perform application-layer inspection, so the presence of layer 7 details confirms traffic is flowing symmetrically through the new firewall.
5. Migrate the remaining spoke VPCs. You can migrate VPCs incrementally, or once you are confident in the new firewall deployment, update the default route in your existing spoke route table to point to the new Network Firewall network function attachment, which moves all remaining spokes that share that route table at once.
6. Optionally, preserve your original NAT gateway Elastic IPs by transferring them to the new egress VPC.
7. Decommission the old combined VPC after you’ve verified that traffic is flowing correctly.

Figure 4: Post-migration architecture for Architecture 2, with the combined VPC eliminated and traffic flowing through the Transit Gateway-attached Network Firewall to a dedicated egress VPC.

For the complete walkthrough of how to perform this migration, see:

• Terraform migration guide
• CloudFormation migration guide
• Manual console migration guide

Both architectures deploy the same new resources and use the same phased cutover approach. The differences are in the starting Transit Gateway routing structure (Architecture 1 has three route tables across two VPCs, Architecture 2 has two route tables in one VPC) and what you clean up at the end (two old VPCs instead of one). Both architectures converge to the same end state. For a detailed comparison, see the migration guide repository.

Regardless of which architecture you’re migrating from, follow these best practices to minimize risk.

The migration guide repository includes starting architecture CloudFormation and Terraform templates for both architectures, so you can deploy the exact starting environment in a development or test account and run through the entire migration process before touching production.

Test before you migrate. Create your new Transit Gateway-attached firewall in parallel with your existing setup. Use a test VPC to validate the new configuration. Verify that logging is working correctly and that the firewall alert logs show layer 7 traffic details, which confirms there is no asymmetric routing. Test both allowed and blocked traffic scenarios before migrating production traffic.

Migrate in phases. Start with a single, non-critical workload VPC. Update only that VPC’s routes to use the new firewall attachment. Monitor and verify application behavior and performance with the application owner before proceeding. When planning your migration order, migrate spoke VPCs that have east-west traffic between each other at the same time. During the phased migration, spokes on different firewall paths will have their east-west traffic traverse two stateful firewalls. Because each stateful firewall independently tracks connection state, traffic that enters through one firewall and returns through another appears as untracked, causing the firewalls to drop or incorrectly handle the return traffic. When you’re confident in the new firewall deployment, you can update the default route in your existing spoke route table to point to the new firewall, which moves all remaining spokes that share that route table at once. Keep your old firewall configuration active until all traffic is migrated.

Prepare a rollback plan. Document your current route table configurations before making changes. Keep your existing firewall and inspection VPC active during migration. If issues arise, revert the route table changes to restore the previous configuration. Decommission old resources after you’ve verified applications are operating as expected.

Preserving your NAT gateway Elastic IPs during migration

An important consideration during migration is maintaining your existing NAT gateway Elastic IP addresses. Many organizations have these IPs allowlisted with external partners, third-party services, or in firewall rules. Changing these IPs would require coordination with multiple stakeholders and could disrupt business operations.

During migration, you need both your old and new deployments to operate simultaneously, so you can validate the new setup without impacting production traffic. This means creating temporary NAT gateways with temporary Elastic IPs in the new egress VPC.

After you’ve confirmed the new firewall deployment is stable and production traffic has been successfully migrated, you can restore your original Elastic IPs. The process differs depending on your architecture:

• For Architecture 1 (separate inspection and egress VPCs), your existing egress VPC and its NAT gateways are independent of the inspection VPC being decommissioned. You can keep them by re-associating the existing egress VPC’s Transit Gateway attachment with the new egress route table and updating the inspection route table to route traffic there instead of the temporary egress VPC. This is a Transit Gateway routing change that takes seconds, doesn’t require deleting or creating any NAT gateways, and doesn’t increase in complexity with the number of Availability Zones. After the re-association, you delete the temporary egress VPC.
• For Architecture 2 (combined inspection and egress VPC), the old VPC contains both the firewall endpoints and the NAT gateways. The simplest path is to decommission it and move the Elastic IPs to the new egress VPC. To do this, you delete the old NAT gateways to free the Elastic IPs, then create new NAT gateways in the new egress VPC with the original Elastic IPs. This requires a brief maintenance window while the new NAT gateways provision and must be repeated for each Availability Zone.

For the detailed step-by-step procedure, see the EIP preservation steps in the migration guide repository.

In this post, we explained what a Transit Gateway-attached network firewall is and how it differs from the traditional inspection VPC model, the reasons to migrate including reduced architectural complexity and flexible cost allocation, what to prepare before starting, and the high-level migration process for the two most common centralized inspection architectures. We also covered best practices for minimizing downtime, handling east-west traffic between spokes during phased migration, and preserving your existing NAT gateway Elastic IPs.

With a Transit Gateway-attached network firewall, AWS manages the firewall endpoints and the underlying VPC on your behalf, eliminating the inspection VPC from your architecture and enabling flexible cost allocation through Transit Gateway metering policies. The phased migration approach covered in this post lets you run both firewalls in parallel, validate the new path with a single spoke VPC, and cut over the rest of your traffic when you are ready.

For detailed step-by-step guidance using Terraform, CloudFormation, or the AWS Management Console for both architectures covered in this post, see the migration guide repository. The repository includes starting architecture templates so you can practice the full migration end-to-end in a test account before migrating your production environment.

If you have feedback about this post, submit comments in the Comments section below.

The financial services industry (FSI) is using AI to transform how financial institutions serve their customers. AI solutions can help proactively manage portfolios, automatically refinance mortgages when rates decrease, and negotiate insurance premiums for customers.

However, this adoption brings new governance, risk, and compliance (GRC) considerations that organizations need to address. To help FSI customers navigate these challenges, AWS is excited to announce an updated AWS User Guide to Governance, Risk, and Compliance for Responsible AI Adoption within Financial Services Industries.

This comprehensive guide provides FSI customers practical considerations for responsible AI adoption across key dimensions including governance, risk management, compliance, data management, model management and AI agent management. It includes detailed AWS service capabilities that customers can use to address these considerations, such as Amazon Bedrock AgentCore, Amazon Bedrock Guardrails, Amazon Bedrock Agents, Amazon SageMaker Autopilot, and Amazon SageMaker Model Monitor.

The guide is available at the AWS Whitepaper portal and is complementary to other AWS resources such as the AWS Responsible Use of AI Guide, AWS Cloud Adoption Framework for AI, AWS Well-Architected Framework – Responsible AI Lens, AWS Well-Architected Framework – Generative AI Lens, and AWS Well-Architected Framework – Machine Learning Lens.

As the regulatory environment and leading practices continue to evolve, we will provide further updates on the AWS Security Blog and AWS Compliance Center. You can also reach out to your AWS account team for help finding the resources you need.

Resources

• AWS Cloud Security
• AWS Compliance
• AWS Security Reference Architecture
• Best Practices for Security, Identity, & Compliance
• Data Protection at AWS
• Zero trust on AWS
• Cryptographic Computing

If you have feedback about this post, submit comments in the Comments section below. If you have questions about this post, contact AWS Support.