networkfirewall
Configures AWS Network Firewall, the managed stateful VPC firewall: deploying a firewall and routing traffic through its endpoints; centralizing inspection for many VPCs with a transit gateway-attached firewall that keeps stateful flows symmetric across Availability Zones; filtering outbound traffic by domain name; logging and rule tuning; TLS inspection with ACM certificates; writing Suricata rules; managing rules as CloudFormation/IaC; blocking an indicator mid-incident; migrating off a third-party firewall appliance; and diagnosing dropped traffic. Applicable when the user wants to inspect or filter VPC traffic at Layer 3 and 4, allow or block outbound domains, manage firewall rules as IaC, or decrypt TLS. Not applicable for AWS WAF Layer 7 rules (waf skill), Gateway Load Balancer appliance inspection (gatewayloadbalancer skill), Route 53 Resolver DNS Firewall (route53 skill), or transit gateway route tables and appliance-mode attachments (transitgateway skill).
- Installs
- 670
- Last 24h
- —
- Trending rank
- —
- Security
- Not audited
Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/aws/agent-toolkit-for-aws --skill networkfirewall- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads networkfirewall automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
Network Firewall
Overview
Domain expertise for configuring AWS Network Firewall, the managed stateful firewall and intrusion prevention service that filters traffic at the perimeter of a VPC using the Suricata inspection engine. Covers placing a firewall in the traffic path and routing traffic through its endpoints, centralizing inspection across VPCs with a transit gateway-attached firewall, filtering outbound traffic by domain name, logging and rule tuning, TLS inspection of encrypted traffic, and diagnosing why traffic is dropped, passed, or unmatched.
This skill is a router. Each customer task maps to a reference file under references/. Read the
matching reference in full before acting, then follow its constraints and steps. The reference
files are self-contained: each carries its own decision tables, constraints, procedure, and
troubleshooting.
Execute commands using the AWS MCP server when connected (sandboxed execution, audit logging,
observability). Fall back to the AWS CLI otherwise. Network Firewall is regional; pass --region
matching the firewall's Region on every aws network-firewall command. Firewall creation,
deletion, and several operations are asynchronous: poll the resource until it reaches the expected
state before depending on it.
Which Network Firewall task do you need?
| Goal | Reference |
|---|---|
| Place a firewall in the path and route VPC traffic through its endpoints | deploying a firewall and routing traffic through it |
| Inspect traffic across many VPCs from one place using a transit gateway-attached firewall | centralizing inspection with a transit gateway-attached firewall |
| Allow or block outbound connections by destination domain name | filtering outbound traffic by domain name |
| Turn on alert, flow, and TLS logging and tune rules from what they show | enabling firewall logging and tuning rules |
| Decrypt and inspect TLS traffic with ACM certificates | inspecting encrypted traffic with TLS inspection |
| Write custom stateful Suricata rules and fix rules that do not match | writing and troubleshooting stateful Suricata rules |
| Block a specific indicator immediately during an active security incident | responding to an active security incident |
| Manage the firewall, policy, and rules in CloudFormation or the CDK | managing firewall rules as IaC |
| Replace a third-party firewall appliance with Network Firewall | migrating from a third-party firewall appliance |
| Find out why traffic is dropped, passed, or not matching a rule | diagnosing dropped or unmatched traffic |
Routing notes
- Deploy before rules. A firewall does nothing until VPC route tables redirect traffic to its endpoints, and nothing reports an error when the routing is missing. Route to the deploying reference first when the firewall is new or traffic is not reaching it, before assuming a rule problem.
- Transit gateway-attached vs inspection VPC. The centralizing reference uses the native transit gateway-attached firewall, which removes the hand-built inspection VPC and its route tables. Route there for multi-VPC or multi-account inspection rather than building an inspection VPC by hand.
- Domain filtering matches the handshake, not the IP. The domain filtering reference matches on the TLS SNI and HTTP host header, not on a DNS lookup, and an allow list silently drops non-matching traffic of the same protocol. Route there for outbound domain control, and reach for TLS inspection when the customer needs the full URL path rather than the domain.
- TLS inspection changes what rules match. The TLS inspection reference is the precondition for
any rule that needs to act on decrypted payload. After TLS termination the decrypted traffic is
plain HTTP to the stateful engine, so port-443 and
tlsrules stop matching. Route there before the customer writes rules against encrypted traffic. - Diagnose by symptom, not by guess. The diagnosing reference reads the endpoint status message
(error vs non-recoverable failure), tests routing symmetry, and checks
HOME_NET, evaluation order, and rule layer before any rewrite. Route there for "traffic is dropped," "traffic passes when it should not," or "my rule does not match." When the symptom is "traffic dropped with no alert log at all," suspect post-quantum ClientHello fragmentation, covered in the diagnosing and logging references. - Incident now vs configuration. The responding reference is for an active incident on an already-deployed firewall: block one indicator immediately, confirm it, and back it out. Route there for "I am under attack, block this now," not through the deploying or rule-authoring references, which are slower configuration workflows.
- Rule authoring vs domain filtering. The writing-Suricata reference covers custom stateful rules (flow keywords, rule order, Suricata engine constraints). Route there for IPS or IDS rule authoring; route to the domain filtering reference when the customer only needs to allow or block domains.
- IaC vs console changes. The managing-as-code reference is for CloudFormation or CDK ownership, where immutable properties (capacity, rule order) make the wrong structure a replacement. Route there when the customer manages the firewall in templates.
- Migration vs first-time setup. The migrating reference is for replacing a third-party firewall appliance with a live rule set and traffic path. Route there for "move off Palo Alto or FortiGate," not the deploying reference, which assumes a greenfield firewall.
Security Considerations
This skill manages network perimeter security, so a misconfiguration weakens the security posture of every VPC behind the firewall. Carry these into each task:
- Default-drop posture. You MUST configure a stateful default action of drop (an allow list of permitted traffic) rather than default-allow, so traffic that no rule matches is blocked rather than passed uninspected. For a network firewall a fail-closed default is a fundamental security control, not an option, and an overly permissive rule set degrades the firewall to a passthrough.
- No silent inspection gaps. You MUST confirm traffic is actually routed through the firewall
endpoints and forwarded to the stateful engine; misconfigured route tables or a stateless
default action other than
aws:forward_to_sfeleave traffic uninspected with no error. - Ephemeral, least-privilege credentials. You MUST use ephemeral, least-privilege credentials (a
time-bound assumed-role session) scoped to the specific
network-firewall:actions and resources each operator needs (e.g.,network-firewall:UpdateRuleGroup,network-firewall:DescribeFirewall), never long-lived access keys or broad administrative access, since these permissions can change what traffic is allowed. - Encrypt logs and firewall data at rest. You MUST encrypt every destination that receives
firewall logs (alert, flow, or TLS), using a customer-managed AWS KMS key on Amazon CloudWatch Logs
log groups (
aws logs associate-kms-key), either SSE-S3 or a customer-managed AWS KMS key on Amazon S3 buckets, and a customer-managed AWS KMS key on Amazon Data Firehose delivery streams, because these logs expose sensitive network metadata (source and destination IPs, domain names, and SNI values). You SHOULD also encrypt the firewall's data at rest with a customer-managed AWS KMS key. - Scope log-destination resource policies with condition keys. You SHOULD scope the resource
policy on each log destination (the Amazon S3 bucket policy, the Amazon CloudWatch Logs resource
policy, and the Amazon Data Firehose delivery-stream policy) with
aws:SourceArn(the firewall's ARN) andaws:SourceAccountcondition keys, so only this firewall in the expected account can write to the destination and another account or service cannot (confused-deputy prevention). - Record API changes with CloudTrail. You SHOULD enable AWS CloudTrail on the account so firewall, policy, rule group, and logging-configuration API changes are recorded for audit and incident review.
- Alarm on critical firewall events. You SHOULD configure CloudWatch alarms to alert on critical firewall events (endpoint failures, policy changes, capacity warnings) so issues are detected and escalated promptly. You MUST encrypt any SNS topic used for these alarm notifications with a customer-managed AWS KMS key and restrict alarm notification recipients to authorized operations and security personnel, since alarm messages can expose sensitive firewall metadata (endpoint status, traffic patterns, and capacity).
- Per-task detail. Each reference carries its own Security Considerations for its workflow; read the matching reference before acting.
Additional Resources
FAQ
What does the networkfirewall skill do?
Configures AWS Network Firewall, the managed stateful VPC firewall: deploying a firewall and routing traffic through its endpoints; centralizing inspection for many VPCs with a transit gateway-attached firewall that keeps stateful flows symmetric across Availability Zones; filtering outbound traffic by domain name; logging and rule tuning; TLS inspection with ACM certificates; writing Suricata rules; managing rules as CloudFormation/IaC; blocking an indicator mid-incident; migrating off a third-party firewall appliance; and diagnosing dropped traffic. Applicable when the user wants to inspect or filter VPC traffic at Layer 3 and 4, allow or block outbound domains, manage firewall rules as IaC, or decrypt TLS. Not applicable for AWS WAF Layer 7 rules (waf skill), Gateway Load Balancer appliance inspection (gatewayloadbalancer skill), Route 53 Resolver DNS Firewall (route53 skill), or transit gateway route tables and appliance-mode attachments (transitgateway skill).
How do I install networkfirewall?
Run npx skills add https://github.com/aws/agent-toolkit-for-aws --skill networkfirewall in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/networkfirewall/ (personal) or .claude/skills/networkfirewall/ (project).
Which AI agents can use networkfirewall?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is networkfirewall safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains networkfirewall?
It is published by aws in aws/agent-toolkit-for-aws, and it is an official skill from the maker of the technology it covers. It has 670 recorded installs.
More from aws/agent-toolkit-for-aws
aws-iam
aws/agent-toolkit-for-aws
Provides verified corrections for IAM behaviors that AI agents frequently get wrong — policy evaluation edge cases, trust policy gotchas, STS session limits, Organizations quirks, and SAML/MFA specifics. Also provides structured workflows for IAM role management and baseline policy generation from application source code or a Terraform plan JSON. Covers condition operator safety (ForAnyValue/ForAllValues with Null checks), bucket policy deny patterns (VPC endpoint restrictions, org paths), confused deputy protection, and service role creation for AWS services (Glue, CloudTrail, Lambda, ECS, etc.) with aws:SourceAccount/aws:SourceArn trust conditions. Applies when creating IAM roles, writing IAM or bucket policies, generating policies from application source code or a Terraform plan JSON, working with STS, Organizations, or condition operators, or any task needing a service or execution role. Does not cover non-IAM authorization like Cognito user-pool policies or app-level RBAC.
aws-serverless
aws/agent-toolkit-for-aws
Routes serverless requests to a compute form factor and the skill that owns it. Applies first to Lambda, API Gateway, EventBridge, Step Functions and event-driven work while the compute, orchestration or integration choice is open — API backends, webhooks, jobs, cron, queue/stream consumers, durable workflows, event routing, Step Functions vs Durable Functions, and Pipes vs native event source mappings for queues and streams. Decides Event Functions on-demand vs Managed Instances, Web Functions, MicroVMs, EventBridge rules/Scheduler/Pipes/bus, HTTP vs REST API. Owns shared Lambda references (cold starts, SnapStart, concurrency, event sources, function URLs, throttling, troubleshooting). Defers to the specialized skill once a request commits to one form factor or service, or describes its defining feature, even unnamed (durable checkpointing and automatic step retries, Firecracker sandbox, managed instances, Node.js server). Not for EC2, ECS/EKS/Fargate or Amplify hosting.
aws-observability
aws/agent-toolkit-for-aws
Builds, configures, debugs, and optimizes AWS observability - operator-symptom questions and detecting Omni vs classic CloudWatch. CloudWatch on an already-reporting service: Log Insights, metric/composite/anomaly alarms, custom metrics/EMF, dashboards, X-Ray/ADOT tracing, canaries, CloudTrail, Dynamic Instrumentation (live breakpoints/snapshots), the Application Signals service map, and fleet health views. CloudWatch Omni on an existing Space: SQL over logs and traces, PromQL over metrics, Omni dashboards, Omni alerts, context graph for root cause, programmatic/IaC access (API/SDK/CLI/CloudFormation), driving Omni from a coding agent or skills, and evaluating AI agent quality from traces - on-demand and online scoring of live traffic, readback, custom evaluators. For first-time setup - creating an Omni Space, granting access, ingestion, or ADOT instrumentation for Application Signals (ServiceEvents, CI/CD metadata) or Omni - use setting-up-cloudwatch-observability. Not for app logging
aws-cdk
aws/agent-toolkit-for-aws
Authors, deploys, and troubleshoots AWS infrastructure using CDK with TypeScript or Python. Covers best practices, stack architecture, and construct patterns. Applies when writing CDK constructs, bootstrapping environments, running cdk deploy/synth/diff, fixing CDK or CloudFormation errors, planning stack structure, importing existing resources, resolving drift, or refactoring stacks without resource replacement.
aws-containers
aws/agent-toolkit-for-aws
Builds and deploys containerized workloads on Elastic Kubernetes Service (EKS), Elastic Container Service (ECS), Fargate, and ECR (Elastic Container Registry). Covers general EKS knowledge, Karpenter, AWS Load Balancer Controller and leveraging various open source Kubernetes projects with EKS. Covers general ECS knowledge, task definitions, Fargate services, ECS Exec, ECS Express Mode and ECS Managed Instances. Covers general Elastic Beanstalk knowledge, Elastic Beanstalk configuration and platforms supported by Elastic Beanstalk. Covers general ECR knowledge, ECR repository setup and lifecycle policies. Includes recommending, enabling, and reading Amazon ECS Action Logs to troubleshoot control-plane failures (deployment rollback/circuit-breaker, task placement, scaling, task replacement). Applies when deploying, debugging, or optimizing containers on AWS. Should be used instead of relying on internal knowledge for these services.
aws-billing-and-cost-management
aws/agent-toolkit-for-aws
Analyze AWS costs, find savings, manage budgets, evaluate Savings Plans and Reserved Instances, right-size EC2/Lambda/RDS/EBS with Compute Optimizer, look up service pricing, query CUR with Athena, detect cost anomalies, scope costs to billing views, and monitor Free Tier usage. Triggers on: AWS bill, cost analysis, reduce spend, savings plan, reserved instance, right-size, budget alert, cost optimization, pricing, free tier, cost anomaly, CUR, cost audit, billing view, billing view ARN.
Popular devops & cloud skills
microsoft-foundry
microsoft/azure-skills
Build, deploy, evaluate, optimize, fine-tune, and manage Microsoft Foundry agents, models, and resources end to end. USE FOR: foundry, azd ai agent, azd provision/deploy, hosted agent scaffold/develop/run/deploy/troubleshoot, prompt agent create, managed harness agent create, GitHub Copilot harness agent, create agent, update agent, add tool to agent, invoke agent, agent insights, evaluate agent, batch eval, continuous eval, continuous monitoring, agent CI/CD, optimize prompt, improve prompt, optimize agent instructions, Agent Optimizer scaffold, dataset curation from traces, deploy model, model fine-tuning (SFT/DPO/RFT), Foundry project, RBAC, role assignment, permissions, quota, capacity, region, deployment failure, AI Services, create Foundry resource, knowledge index, customize deployment, onboard, availability, training-data, grader, distillation, large file upload. DO NOT USE FOR: Azure Functions, App Service, general Azure deploy (use azure-deploy), general Azure prep (use azure
azure-diagnostics
microsoft/azure-skills
Debug Azure production issues on Azure using AppLens, Azure Monitor, resource health, and safe triage. WHEN: debug production issues, troubleshoot app service, app service high CPU, app service deployment failure, troubleshoot container apps, container app 503 or target port mismatch, troubleshoot functions, function telemetry missing or stopped after a config/connection-string change, troubleshoot AKS, VM RDP, Linux SSH, VM black screen, can't connect to VM, reset VM password, NSG or firewall blocking, kubectl cannot connect, kube-system/CoreDNS failures, pod pending, crashloop, node not ready, upgrade failures, analyze logs, KQL, insights, image pull failures, cold start issues, health probe failures, resource health, root cause of errors, troubleshoot event hubs, troubleshoot service bus, messaging SDK error, AMQP connection failure, message lock lost, lock renewal during long-running processing, service bus dead letter.
azure-prepare
microsoft/azure-skills
Prepare azd-based Azure projects for deployment: generates azure.yaml, infrastructure (Bicep/Terraform), and Dockerfiles for the Azure Developer CLI (azd) workflow. USE ONLY when the user explicitly wants to use azd as the deployment tool, or the project already has an azure.yaml file. DO NOT USE FOR: non-azd deployments, Python App Service code-only deploys (use python-appservice-deploy), or cross-cloud migration (use azure-cloud-migrate). WHEN: prepare app for azd, create azure.yaml, set up azd infrastructure, modernize app for Azure with azd, deploy with azd, function app, timer trigger, service bus trigger, event-driven function, managed identity, generate Bicep, generate Terraform, create and deploy to Azure.
azure-ai
microsoft/azure-skills
Use for Azure AI: Search, Speech, OpenAI, Document Intelligence. Helps with search, vector/hybrid search, speech-to-text, text-to-speech, transcription, OCR. WHEN: AI Search, query search, vector search, hybrid search, semantic search, speech-to-text, text-to-speech, transcribe, OCR, convert text to speech.
azure-deploy
microsoft/azure-skills
Execute Azure deployments for ALREADY-PREPARED applications that have existing .azure/deployment-plan.md and infrastructure files. DO NOT use this skill when the user asks to CREATE a new application — use azure-prepare instead. This skill runs azd up, azd deploy, terraform apply, and az deployment commands with built-in error recovery. Requires .azure/deployment-plan.md from azure-prepare and validated status from azure-validate. WHEN: "run azd up", "run azd deploy", "execute deployment", "push to production", "push to cloud", "go live", "ship it", "bicep deploy", "terraform apply", "publish to Azure", "launch on Azure". DO NOT USE WHEN: "create and deploy", "build and deploy", "create a new app", "set up infrastructure", "create and deploy to Azure using Terraform" — use azure-prepare for these.
azure-validate
microsoft/azure-skills
Pre-deployment validation for Azure readiness. Run deep checks on configuration, infrastructure (Bicep or Terraform), RBAC role assignments, managed identity permissions, and prerequisites before deploying. WHEN: validate my app, check deployment readiness, run preflight checks, verify configuration, check if ready to deploy, validate azure.yaml, validate Bicep, test before deploying, troubleshoot deployment errors, validate Azure Functions, validate function app, validate serverless deployment, verify RBAC roles, check role assignments, review managed identity permissions, what-if analysis, validate Container Apps deployment.