Chainguard Container for chisel

A fast TCP/UDP tunnel over HTTP

Chainguard Containers are regularly-updated, secure-by-default container images.

Download this Container Image

For those with access, this container image is available on cgr.dev:

docker pull cgr.dev/ORGANIZATION/chisel:latest

Be sure to replace the ORGANIZATION placeholder with the name used for your organization's private repository within the Chainguard Registry.

What is Chisel?

Chisel is a fast TCP/UDP tunnel, transported over HTTP, secured via SSH. It allows you to create secure tunnels through firewalls and NAT devices. This container image provides both server and client functionality for creating encrypted tunnels.

Usage

The chisel container can be run in two modes: server and client.

Server Mode

Start a chisel server with authentication:

docker run -p 8080:8080 --name chisel-server -d \
  cgr.dev/$ORGANIZATION/chisel server --auth username:password

Start a server without authentication (not recommended for production):

docker run -p 8080:8080 --name chisel-server -d \
  cgr.dev/$ORGANIZATION/chisel server

Client Mode

Connect to a chisel server and create a tunnel:

docker run -p 28080:28080 --name chisel-client -d \
  cgr.dev/$ORGANIZATION/chisel client --auth username:password \
  http://server-host:8080 28080:target-host:80

Complete Example

Here's a complete example that demonstrates setting up a tunnel to access an nginx server:

1. Create a Docker network:

docker network create chisel-test

2. Start an nginx server:

docker run --network chisel-test -p 18080:8080 --name nginx -d \
  cgr.dev/$ORGANIZATION/nginx

3. Start the chisel server:

docker run --network chisel-test -p 8080:8080 --name chisel-server -d \
  cgr.dev/$ORGANIZATION/chisel server --auth testuser:S3cr3tP@ssword

4. Start the chisel client to create a tunnel:

docker run --network chisel-test -p 28080:28080 --name chisel-client -d \
  cgr.dev/$ORGANIZATION/chisel client --auth testuser:S3cr3tP@ssword \
  http://chisel-server:8080 28080:nginx:8080

5. Test the tunnel:

# Access nginx directly
curl http://localhost:18080

# Access nginx through the chisel tunnel
curl http://localhost:28080

Common Use Cases

• Bypassing firewalls: Create tunnels through restrictive network environments
• Accessing internal services: Expose internal services through a single HTTP endpoint
• Reverse tunnels: Allow external access to services behind NAT
• Port forwarding: Forward local ports to remote services

Security Notes

• Always use authentication (--auth username:password) in production environments
• Consider using TLS/HTTPS for the transport layer when possible
• Regularly rotate authentication credentials
• Monitor tunnel usage and connections

Troubleshooting

Check server logs:

docker logs chisel-server

Check client logs:

docker logs chisel-client

The server should show "Listening on" and the client should show "Connected" when the tunnel is established successfully.

What are Chainguard Containers?

Chainguard Containers are minimal container images that are secure by default.

In many cases, the Chainguard Containers tagged as :latest contain only an open-source application and its runtime dependencies. These minimal container images typically do not contain a shell or package manager. Chainguard Containers are built with Wolfi, our Linux undistro designed to produce container images that meet the requirements of a more secure software supply chain.

The main features of Chainguard Containers include:

• Minimal design, without unnecessary software bloat
• Daily builds to ensure container images are up-to-date with available security patches
• High quality build-time SBOMs attesting to the provenance of all artifacts within the image
• Verifiable signatures provided by Sigstore
• Reproducible builds with Cosign and apko (read more about reproducibility)

For cases where you need container images with shells and package managers to build or debug, most Chainguard Containers come paired with a -dev variant.

Although the -dev container image variants have similar security features as their more minimal versions, they feature additional software that is typically not necessary in production environments. We recommend using multi-stage builds to leverage the -dev variants, copying application artifacts into a final minimal container that offers a reduced attack surface that won’t allow package installations or logins.

Learn More

To better understand how to work with Chainguard Containers, please visit Chainguard Academy and Chainguard Courses.

In addition to Containers, Chainguard offers VMs and Libraries. Contact Chainguard to access additional products.

Trademarks

This software listing is packaged by Chainguard. The trademarks set forth in this offering are owned by their respective companies, and use of them does not imply any affiliation, sponsorship, or endorsement by such companies.