Chisel
Fast TCP and UDP tunnel over HTTP secured with SSH, shipped as a single Go binary.
Technical Architecture & Overview
Chisel tunnels TCP and UDP over HTTP transports secured with SSH, in a single executable that is a client or server. It supports SOCKS5 proxying, reverse port forwarding, and multiplexed tunnels through restrictive firewalls, and it doubles as a self-hosted ngrok replacement in development workflows. Its small footprint made it a fixture of network pivoting, though reverse TUN tools now compete for that role.
Targeted Technical Use Cases
Reliable tunneling over HTTP-only egress paths during authorized testing, or dev tunneling behind NAT.
Evaluation & Trade-offs
Core Strengths
- +Single static binary, cross-platform.
- +HTTP transport crosses restrictive egress filters.
- +Mature and widely documented.
Trade-Offs & Limitations
- -Layer-4 only; layer-3 pivoting needs a TUN-based tool.
- -Attackers use it too, so it is widely signatured.
Defensive Security Application
Testing egress filtering by demonstrating what tunneling survives the current controls.
Frequently Asked Questions
What is Chisel?→
Chisel tunnels TCP and UDP over HTTP transports secured with SSH, in a single executable that is a client or server. It supports SOCKS5 proxying, reverse port forwarding, and multiplexed tunnels through restrictive firewalls, and it doubles as a self-hosted ngrok replacement in development workflows. Its small footprint made it a fixture of network pivoting, though reverse TUN tools now compete for that role.
What is Chisel used for?→
Reliable tunneling over HTTP-only egress paths during authorized testing, or dev tunneling behind NAT.
What are the strengths of Chisel?→
- +Single static binary, cross-platform.
- +HTTP transport crosses restrictive egress filters.
- +Mature and widely documented.
What are the limitations of Chisel?→
- +Layer-4 only; layer-3 pivoting needs a TUN-based tool.
- +Attackers use it too, so it is widely signatured.
How is Chisel used defensively?→
Testing egress filtering by demonstrating what tunneling survives the current controls.