
Chisel is a fast TCP tunnel, transported over HTTP, secured via SSH.
Single executable including both client and server. Written in Go (Golang). Chisel is mainly useful for passing through firewalls, though it can also be used to provide a secure endpoint into your network. Chisel is very similar to crowbar though achieves much higher performance.
Features
- Easy to use
- Performant*
- Encrypted connections using the SSH protocol (via
crypto/ssh
) - Authenticated connections; authenticated client connections with a users config file, authenticated server connections with fingerprint matching.
- Client auto-reconnects with exponential backoff
- Client can create multiple tunnel endpoints over one TCP connection
- Client can optionally pass through HTTP CONNECT proxies
- Server optionally doubles as a reverse proxy
- Server optionally allows SOCKS5 connections (See guide below)
Usage
$ chisel --help Usage: chisel [command] [--help] Version: X.Y.Z Commands: server - runs chisel in server mode client - runs chisel in client mode Read more: https://github.com/jpillora/chisel
Security
Encryption is always enabled. When you start up a chisel server, it will generate an in-memory ECDSA public/private key pair. The public key fingerprint will be displayed as the server starts. Instead of generating a random key, the server may optionally specify a key seed, using the --key
option, which will be used to seed the key generation. When clients connect, they will also display the server’s public key fingerprint. The client can force a particular fingerprint using the --fingerprint
option. See the --help
above for more information.
Authentication
Using the --authfile
option, the server may optionally provide a user.json
configuration file to create a list of accepted users. The client then authenticates using the --auth
option. See users.json for an example authentication configuration file. See the --help
above for more information.
Known Issues
- WebSockets support is required
- IaaS providers all will support WebSockets
- Unless an unsupporting HTTP proxy has been forced in front of you, in which case I’d argue that you’ve been downgraded to PaaS.
- PaaS providers vary in their support for WebSockets
- Heroku has full support
- Openshift has full support though connections are only accepted on ports 8443 and 8080
- Google App Engine has no support (Track this on their repo)
- IaaS providers all will support WebSockets