Generated banner for Transitgateway
Generated logo for Transitgateway

Transitgateway

AWSOfficialPublished by AWS

  • Skill
  • Workflow
  • Cloud and DevOps
  • Apache-2.0
  • No issues found

From the author

Configures AWS Transit Gateway: creating a hub and attaching VPCs, segmenting traffic with route tables, centralizing egress and inspection through a hub (appliances or a Gateway Load Balancer endpoint), forcing east-west traffic between VPCs through AWS Network Firewall, connecting on-premises networks over the transit-gateway side of a Site-to-Site VPN or Direct Connect attachment (including ECMP to aggregate bandwidth across multiple VPN tunnels), peering transit gateways across Regions, migrating from a VPC peering mesh, and routing IP multicast. Applicable when connecting many VPCs through one router, isolating environments, forcing VPC-to-VPC traffic through a central Network Firewall, reaching on-premises over the hub, linking Regions, or moving off a peering mesh. Not applicable for single-VPC routing, VPC peering between two VPCs (vpcpeering skill), Direct Connect gateway or virtual interface setup (directconnect skill), or Route 53 DNS work.
— the description by AWS

AutoGineer summary

Written by AutoGineer from the skill’s own files, not by the author

This skill provides a structured framework for deploying and managing AWS Transit Gateway, acting as a regional network hub. It streamlines the connection of multiple VPCs and on-premises networks, replacing complex point-to-point peering meshes with a centralized routing architecture. The skill covers the full lifecycle of transit gateway operations, including hub creation, traffic segmentation, centralized egress and inspection, hybrid connectivity, and inter-region peering.

What it does

  • Creates and configures regional transit gateway hubs and VPC attachments.
  • Implements traffic segmentation using custom route tables to isolate or share network environments.
  • Centralizes egress and inspection traffic through dedicated VPCs using appliances or Gateway Load Balancer endpoints.
  • Facilitates hybrid connectivity via Site-to-Site VPN and Direct Connect, including ECMP for bandwidth aggregation.
  • Manages inter-region peering and migration from existing VPC peering meshes.
  • Configures IP multicast routing across attached VPCs.

When to use it

  • When you need to connect a large number of VPCs through a single, manageable router.
  • When you require centralized inspection of traffic between VPCs or to the internet.
  • When you need to isolate network environments while maintaining controlled access to shared services.
  • When you are migrating from a complex, unmanageable VPC peering mesh.
  • When you need to connect on-premises data centers to multiple VPCs efficiently.

Advantages

  • Reduces network complexity by replacing point-to-point connections with a hub-and-spoke model.
  • Enables consistent security enforcement through centralized inspection points.
  • Supports scalable hybrid connectivity with options for performance optimization.
  • Provides granular control over traffic flow via route table associations and propagations.
  • Simplifies management of multi-region and multi-VPC network architectures.

Usage examples

“How do I set up a transit gateway to connect three VPCs and ensure they are isolated from each other?”
The agent will guide you through creating the transit gateway, attaching the VPCs, and configuring separate route tables to prevent cross-VPC communication.
“I need to route all outbound traffic from my spoke VPCs through a central inspection VPC using a Gateway Load Balancer.”
The agent will provide the steps to configure the central inspection VPC, set up the GWLB endpoint, and update route tables to force traffic through the inspection path.
“Can you help me enable ECMP for my multiple VPN tunnels to increase bandwidth?”
The agent will verify that you are using dynamic BGP routing and guide you through the configuration to aggregate bandwidth across your VPN tunnels.
“We are moving off a VPC peering mesh. How do we migrate to a transit gateway without downtime?”
The agent will outline a migration strategy, including creating the transit gateway, establishing attachments, and incrementally updating routes to transition traffic.

Install

  1. Download the skill as a ZIP:

    https://autogineer.com/agent-skills/aws/transitgateway/download
  2. Unzip it into the cross-client skills folder of your project:

    mkdir -p .agents/skills && unzip transitgateway.zip -d .agents/skills

Documentation by AWS

AWS Transit Gateway

Overview

Domain expertise for configuring AWS Transit Gateway, the Regional network hub that connects many VPCs and on-premises networks through a single router instead of a mesh of point-to-point connections. Covers building the hub and attaching VPCs, segmenting traffic with route tables, centralizing egress and inspection, east-west inspection with AWS Network Firewall, hybrid connectivity over Site-to-Site VPN and Direct Connect, inter-Region peering, migrating off a VPC peering mesh, and IP multicast.

This skill is a router. Each customer task maps to a procedure 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. All CLI operations require least-privilege, ephemeral credentials (an assumed IAM role through AWS STS or AWS IAM Identity Center / SSO), never long-lived IAM user access keys. A transit gateway is a Regional resource: run each aws ec2 transit gateway command in the Region that holds the hub.

Which Transit Gateway task do you need?

GoalReference
Create a Regional hub and connect VPCs to itcreating a transit gateway and attaching VPCs
Isolate some VPCs while letting others share servicessegmenting traffic with route tables
Send all spoke traffic out through one inspected egress VPCcentralizing egress and inspection
Inspect traffic between VPCs with AWS Network Firewallinspecting east-west traffic with Network Firewall
Reach on-premises networks over Site-to-Site VPN or Direct Connectconnecting on-premises networks
Link transit gateways in two Regions over the AWS networkpeering transit gateways across Regions
Move off a VPC peering mesh without dropping trafficmigrating from VPC peering
Distribute IP multicast across attached VPCsrouting multicast traffic

Routing notes

  • Decide segmentation before you build. "Default route table association" and "Default route table propagation" are on by default, which wires every attachment into one open mesh. If the customer plans isolated environments, the creating reference disables the defaults up front and hands off to the segmenting reference. Retrofitting isolation onto an open hub is a re-architect.

  • North-south egress vs east-west inspection. Centralizing egress sends spoke traffic out to the internet through a central VPC. East-west inspection keeps traffic between spokes internal and forces it through a firewall on the way. They look similar but use different route table recipes. Match the reference to the direction of traffic the customer actually has.

  • Appliance vs Gateway Load Balancer for inspection. Raw third-party appliances and a Gateway Load Balancer (GWLB) endpoint are two paths to the same goal. GWLB is the recommended approach for new designs. Both live in the centralizing-egress reference; appliance mode and the GWLB endpoint route table entries differ and the reference covers each.

  • Appliance mode is required for stateful cross-Availability-Zone inspection, with a tradeoff. Appliance mode keeps each flow on one Availability Zone's appliance so request and response do not split. It also disables cross-Availability-Zone failover for that attachment, so the inspection design must pair it with health-check-based failover. Both the egress and east-west references carry this.

  • Transit gateway side vs Direct Connect side. The connecting-on-premises reference covers the transit gateway side: Site-to-Site VPN attachment options, route propagation, and equal-cost multi-path (ECMP). The Direct Connect gateway and virtual interface setup belongs to the separate directconnect skill. Do not restate the Direct Connect side here.

Security considerations

A transit gateway is the central routing point for many VPCs and on-premises networks, so a misconfiguration here has blast radius across every attached network. Apply these controls regardless of the specific task; each per-task reference carries the detail.

  • You MUST enable Transit Gateway Flow Logs for traffic visibility, audit, and incident response across the hub, and MUST enable encryption at rest on the destination (a KMS key on the CloudWatch log group, or SSE-KMS on the S3 bucket).

  • You MUST, when a KMS key encrypts a flow log destination (CloudWatch log group or S3 bucket) or a CloudTrail destination, scope the KMS key policy with condition keys (aws:SourceArn, aws:SourceAccount, and kms:ViaService) so only the specific log group, bucket, or trail in the expected account and service can use the key, preventing cross-account or cross-service misuse.

  • You SHOULD apply least-privilege IAM for transit gateway administration, avoiding service wildcards and FullAccess policies, restricting who can create attachments, modify route tables, and change associations or propagations.

  • You SHOULD ensure Site-to-Site VPN tunnels use strong encryption (for example AES-256-GCM with IKEv2) and enable tunnel logging to CloudWatch Logs with encryption enabled (a KMS key) to protect sensitive connection state and IKE negotiation detail from unauthorized access (see the connecting on-premises networks reference).

  • You MUST treat a misconfigured transit gateway route table as a security risk, since wrong associations or propagations can expose workloads across environments meant to stay isolated (see the segmenting traffic reference).

  • You MUST enable AWS CloudTrail to detect unauthorized changes to transit gateway route tables, associations, and propagations, MUST enable encryption at rest on the CloudTrail destination (a KMS key), and use AWS Config rules to detect drift from the intended design.

Additional Resources

Files

LICENSE


                                 Apache License
                           Version 2.0, January 2004
                        http://www.apache.org/licenses/

   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION

   1. Definitions.

      "License" shall mean the terms and conditions for use, reproduction,
      and distribution as defined by Sections 1 through 9 of this document.

      "Licensor" shall mean the copyright owner or entity authorized by
      the copyright owner that is granting the License.

      "Legal Entity" shall mean the union of the acting entity and all
      other entities that control, are controlled by, or are under common
      control with that entity. For the purposes of this definition,
      "control" means (i) the power, direct or indirect, to cause the
      direction or management of such entity, whether by contract or
      otherwise, or (ii) ownership of fifty percent (50%) or more of the
      outstanding shares, or (iii) beneficial ownership of such entity.

      "You" (or "Your") shall mean an individual or Legal Entity
      exercising permissions granted by this License.

      "Source" form shall mean the preferred form for making modifications,
      including but not limited to software source code, documentation
      source, and configuration files.

      "Object" form shall mean any form resulting from mechanical
      transformation or translation of a Source form, including but
      not limited to compiled object code, generated documentation,
      and conversions to other media types.

      "Work" shall mean the work of authorship, whether in Source or
      Object form, made available under the License, as indicated by a
      copyright notice that is included in or attached to the work
      (an example is provided in the Appendix below).

      "Derivative Works" shall mean any work, whether in Source or Object
      form, that is based on (or derived from) the Work and for which the
      editorial revisions, annotations, elaborations, or other modifications
      represent, as a whole, an original work of authorship. For the purposes
      of this License, Derivative Works shall not include works that remain
      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including
      the original version of the Work and any modifications or additions
      to that Work or Derivative Works thereof, that is intentionally
      submitted to Licensor for inclusion in the Work by the copyright owner
      or by an individual or Legal Entity authorized to submit on behalf of
      the copyright owner. For the purposes of this definition, "submitted"
      means any form of electronic, verbal, or written communication sent
      to the Licensor or its representatives, including but not limited to
      communication on electronic mailing lists, source code control systems,
      and issue tracking systems that are managed by, or on behalf of, the
      Licensor for the purpose of discussing and improving the Work, but
      excluding communication that is conspicuously marked or otherwise
      designated in writing by the copyright owner as "Not a Contribution."

      "Contributor" shall mean Licensor and any individual or Legal Entity
      on behalf of whom a Contribution has been received by Licensor and
      subsequently incorporated within the Work.

   2. Grant of Copyright License. Subject to the terms and conditions of
      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      copyright license to reproduce, prepare Derivative Works of,
      publicly display, publicly perform, sublicense, and distribute the
      Work and such Derivative Works in Source or Object form.

   3. Grant of Patent License. Subject to the terms and conditions of
      this License, each Contributor hereby grants to You a perpetual,
      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
      (except as stated in this section) patent license to make, have made,
      use, offer to sell, sell, import, and otherwise transfer the Work,
      where such license applies only to those patent claims licensable
      by such Contributor that are necessarily infringed by their
      Contribution(s) alone or by combination of their Contribution(s)
      with the Work to which such Contribution(s) was submitted. If You
      institute patent litigation against any entity (including a
      cross-claim or counterclaim in a lawsuit) alleging that the Work
      or a Contribution incorporated within the Work constitutes direct
      or contributory patent infringement, then any patent licenses
      granted to You under this License for that Work shall terminate
      as of the date such litigation is filed.

   4. Redistribution. You may reproduce and distribute copies of the
      Work or Derivative Works thereof in any medium, with or without
      modifications, and in Source or Object form, provided that You
      meet the following conditions:

      (a) You must give any other recipients of the Work or
          Derivative Works a copy of this License; and

      (b) You must cause any modified files to carry prominent notices
          stating that You changed the files; and

      (c) You must retain, in the Source form of any Derivative Works
          that You distribute, all copyright, patent, trademark, and
          attribution notices from the Source form of the Work,
          excluding those notices that do not pertain to any part of
          the Derivative Works; and

      (d) If the Work includes a "NOTICE" text file as part of its
          distribution, then any Derivative Works that You distribute must
          include a readable copy of the attribution notices contained
          within such NOTICE file, excluding those notices that do not
          pertain to any part of the Derivative Works, in at least one
          of the following places: within a NOTICE text file distributed
          as part of the Derivative Works; within the Source form or
          documentation, if provided along with the Derivative Works; or,
          within a display generated by the Derivative Works, if and
          wherever such third-party notices normally appear. The contents
          of the NOTICE file are for informational purposes only and
          do not modify the License. You may add Your own attribution
          notices within Derivative Works that You distribute, alongside
          or as an addendum to the NOTICE text from the Work, provided
          that such additional attribution notices cannot be construed
          as modifying the License.

      You may add Your own copyright statement to Your modifications and
      may provide additional or different license terms and conditions
      for use, reproduction, or distribution of Your modifications, or
      for any such Derivative Works as a whole, provided Your use,
      reproduction, and distribution of the Work otherwise complies with
      the conditions stated in this License.

   5. Submission of Contributions. Unless You explicitly state otherwise,
      any Contribution intentionally submitted for inclusion in the Work
      by You to the Licensor shall be under the terms and conditions of
      this License, without any additional terms or conditions.
      Notwithstanding the above, nothing herein shall supersede or modify
      the terms of any separate license agreement you may have executed
      with Licensor regarding such Contributions.

   6. Trademarks. This License does not grant permission to use the trade
      names, trademarks, service marks, or product names of the Licensor,
      except as required for reasonable and customary use in describing the
      origin of the Work and reproducing the content of the NOTICE file.

   7. Disclaimer of Warranty. Unless required by applicable law or
      agreed to in writing, Licensor provides the Work (and each
      Contributor provides its Contributions) on an "AS IS" BASIS,
      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
      implied, including, without limitation, any warranties or conditions
      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
      PARTICULAR PURPOSE. You are solely responsible for determining the
      appropriateness of using or redistributing the Work and assume any
      risks associated with Your exercise of permissions under this License.

   8. Limitation of Liability. In no event and under no legal theory,
      whether in tort (including negligence), contract, or otherwise,
      unless required by applicable law (such as deliberate and grossly
      negligent acts) or agreed to in writing, shall any Contributor be
      liable to You for damages, including any direct, indirect, special,
      incidental, or consequential damages of any character arising as a
      result of this License or out of the use or inability to use the
      Work (including but not limited to damages for loss of goodwill,
      work stoppage, computer failure or malfunction, or any and all
      other commercial damages or losses), even if such Contributor
      has been advised of the possibility of such damages.

   9. Accepting Warranty or Additional Liability. While redistributing
      the Work or Derivative Works thereof, You may choose to offer,
      and charge a fee for, acceptance of support, warranty, indemnity,
      or other liability obligations and/or rights consistent with this
      License. However, in accepting such obligations, You may act only
      on Your own behalf and on Your sole responsibility, not on behalf
      of any other Contributor, and only if You agree to indemnify,
      defend, and hold each Contributor harmless for any liability
      incurred by, or claims asserted against, such Contributor by reason
      of your accepting any such warranty or additional liability.

Requirements and compatibility

Works with: Claude Code, Claude apps, OpenAI Codex, GitHub Copilot, Cursor, Gemini CLI, Kiro, OpenCode, Goose, Amp, Roo Code, JetBrains Junie, Factory Droid, Devin (ex-Windsurf), Mistral Vibe, OpenHands, Letta

“Works with” means the tool reads the open Agent Skills format; a skill written for one tool may use features others lack.

Needs: Needs an MCP server

Security

No issues found by our static scan· No issues found

A static scan is not a guarantee. Skills are third-party content: review a skill before you let an agent use it.

Attribution and licence

Published by
AWS
Publisher
AWS (Official)
Source
aws/agent-toolkit-for-aws · skills/specialized-skills/networking-and-content-delivery-skills/transitgateway · commit 0a218f8
Licence
Apache License 2.0 (redistribution allowed)
  • LICENSE (added by AutoGineer from LICENSE)
  • NOTICE (added by AutoGineer from NOTICE)
  • ATTRIBUTION.md (written by AutoGineer)
Synced

AutoGineer is not affiliated with or endorsed by AWS or AWS.

Download ZIP

The ZIP holds the skill’s files, its licence files and an ATTRIBUTION.md. Download transitgateway.zip