rustunnel CLI Client Guide — every flag, command, and config option

This is the complete reference for the rustunnel CLI — every flag, command, and config option. New to rustunnel? Start with the Quickstart for a three-step walkthrough, or the self-hosting guide if you want to run your own server.

Installation

From source (recommended)

Requires Rust 1.75 or later.

git clone https://github.com/joaoh82/rustunnel
cd rustunnel
cargo build --release -p rustunnel-client
sudo install -Dm755 target/release/rustunnel /usr/local/bin/rustunnel

Or use the Makefile shortcut:

make deploy-client

Verify

rustunnel --version

Quick Start

# 1. Get an auth token
#    → Sign up at https://rustunnel.com, then go to Dashboard → API Keys → Create token

# 2. Create a config file interactively
rustunnel setup
# → prompts for region and auth token, writes ~/.rustunnel/config.yml

# 3. Expose a local web server running on port 3000
rustunnel http 3000

# 4. Expose a raw TCP service (e.g. SSH on port 22)
rustunnel tcp 22

After connecting, the terminal displays the public URL:

╭────────────────────────────────────────────────────────────╮
│                         rustunnel                          │
├────────────────────────────────────────────────────────────┤
│  HTTP [myapp] → localhost:3000                             │
│   https://myapp.tunnel.example.com                        │
╰────────────────────────────────────────────────────────────╯

  ✓ Tunnels active. Press Ctrl-C to quit.

Configuration File

The client reads ~/.rustunnel/config.yml automatically. CLI flags always override file values.

Full example

# Tunnel server address (required — choose a region)
server: eu.edge.rustunnel.com:4040

# Authentication token (required)
auth_token: rt_live_abc123...

# Skip TLS certificate verification — local dev ONLY, never use in production
insecure: false

# Region preference: auto (probe & pick nearest), or eu / us / ap.
# Omit for self-hosted / single-server setups.
region: auto

# Named tunnel definitions used by `rustunnel start`
tunnels:
  web:
    proto: http
    local_port: 3000
    local_host: localhost       # optional, defaults to localhost
    subdomain: myapp            # optional, requests a specific subdomain

  api:
    proto: http
    local_port: 8080
    subdomain: myapi

  database:
    proto: tcp
    local_port: 5432

Field reference

Field	Type	Default	Description
`server`	string	—	Tunnel server host:port (e.g. `eu.edge.rustunnel.com:4040`)
`auth_token`	string	—	Authentication token issued by the server
`insecure`	bool	`false`	Skip TLS certificate verification (dev only)
`region`	string	omit	`auto` (probe nearest), `eu`, `us`, `ap`. Omit for self-hosted setups.
`tunnels`	map	`{}`	Named tunnel definitions (used by `rustunnel start`)
`tunnels.<name>.proto`	string	—	`http` or `tcp`
`tunnels.<name>.local_port`	integer	—	Local port to forward
`tunnels.<name>.local_host`	string	`localhost`	Local hostname to connect to
`tunnels.<name>.subdomain`	string	auto-assigned	Requested HTTP subdomain

Commands

`setup` — Interactive config wizard

Create (or overwrite) ~/.rustunnel/config.yml through a guided prompt sequence.

rustunnel setup

Prompts:

Prompt	Default	Description
Region	`auto`	`auto` (probe nearest), `eu`, `us`, `ap`, or `self-hosted`
Auth token	(blank)	Token issued by the server; leave empty to fill in later
Server address	(auto-resolved)	Only prompted when `self-hosted` is selected

Region behavior:

Choice	Server resolution
`eu` / `us` / `ap`	Auto-set to `<region>.edge.rustunnel.com:4040`
`auto`	Probes all regions, picks the nearest by latency
`self-hosted`	Prompts for your server address

Behaviour:

Creates ~/.rustunnel/ if the directory doesn’t exist.
If a config file already exists it is overwritten — a backup is not kept, so copy the old file first if you want to preserve it.
Writes a commented tunnels: block with HTTP and TCP examples so you can see the structure right away.
Prints Created: or Updated: with the full path when done.

Example session (auto region):

rustunnel setup — create ~/.rustunnel/config.yml

Region [auto / eu / us / ap / self-hosted] (default: auto):
  Selecting nearest region… eu 12ms · us 143ms · ap 311ms · → eu (Helsinki, FI) 12ms
  Server set to: eu.edge.rustunnel.com:4040

Auth token (leave blank to skip): rt_live_abc123xyz

Created: /Users/alice/.rustunnel/config.yml
Run `rustunnel start` to connect using this config.

Example session (self-hosted):

rustunnel setup — create ~/.rustunnel/config.yml

Region [auto / eu / us / ap / self-hosted] (default: auto): self-hosted

Tunnel server address: tunnel.internal.corp:4040

Auth token (leave blank to skip): my-token

Created: /Users/alice/.rustunnel/config.yml
Run `rustunnel start` to connect using this config.

Generated file (managed):

# rustunnel configuration
# Documentation: https://github.com/joaoh82/rustunnel

server: eu.edge.rustunnel.com:4040
auth_token: rt_live_abc123xyz
region: auto

# tunnels:
#   web:
#     proto: http
#     local_port: 3000
#   api:
#     proto: http
#     local_port: 8080
#     subdomain: myapi
#   database:
#     proto: tcp
#     local_port: 5432

Generated file (self-hosted):

# rustunnel configuration
# Documentation: https://github.com/joaoh82/rustunnel

server: tunnel.internal.corp:4040
auth_token: my-token
# region: not applicable (self-hosted)

# tunnels:
#   ...

After running setup, uncomment and fill in the tunnels: section then run rustunnel start, or use rustunnel http <port> / rustunnel tcp <port> directly.

`http` — HTTP tunnel

Expose a local HTTP/HTTPS service through the tunnel server.

rustunnel http <port> [options]

Arguments:

Argument	Description
`<port>`	Local TCP port to forward (e.g. `3000`)

Options:

Flag	Default	Description
`--subdomain <name>`	auto-assigned	Request a specific subdomain (e.g. `myapp` → `myapp.eu.edge.rustunnel.com`)
`--server <host:port>`	from config	Override the server address (bypasses region selection)
`--token <token>`	from config	Override the auth token
`--local-host <host>`	`localhost`	Local hostname to forward to
`--region <id>`	from config	Region to connect to: `eu`, `us`, `ap`, or `auto`. Ignored if `--server` is set.
`--no-reconnect`	off	Exit instead of reconnecting on failure
`--insecure`	off	Skip TLS verification (dev only)

Examples:

# Expose port 3000 — auto-selects the nearest region
rustunnel http 3000

# Connect to a specific region
rustunnel http 3000 --region eu

# Request a specific subdomain
rustunnel http 3000 --subdomain myapp

# Forward to a non-localhost service
rustunnel http 8080 --local-host 192.168.1.10

# One-shot connection (exit on disconnect instead of reconnecting)
rustunnel http 3000 --no-reconnect

# Use an explicit server address (bypasses region selection)
rustunnel http 3000 --server tunnel.example.com:9000 --token rt_live_abc123

`tcp` — TCP tunnel

Expose any raw TCP service (database, SSH, game server, etc.).

rustunnel tcp <port> [options]

Arguments:

Argument	Description
`<port>`	Local TCP port to forward

Options: Same as http except --subdomain has no effect for TCP tunnels. --region still works. Examples:

# Expose a local PostgreSQL instance
rustunnel tcp 5432

# Expose SSH on a non-standard port
rustunnel tcp 2222 --local-host 10.0.0.5

The server assigns a random public port from its configured TCP port range. The public address is displayed in the startup box.

`start` — Multi-tunnel mode

Start all tunnels defined in a config file simultaneously.

rustunnel start [--config <path>]

Options:

Flag	Default	Description
`-c, --config <path>`	`~/.rustunnel/config.yml`	Path to a config file

Example:

# Use default config file
rustunnel start

# Use a custom config file
rustunnel start --config /etc/rustunnel/production.yml

start always reconnects automatically (equivalent to running each tunnel without --no-reconnect). At least one tunnel must be defined in the config file or the command exits with an error.

Multiple backends (load balancing)

When start is given two or more tunnels with the same (group, group_key), the server treats them as one logical pool — inbound traffic is dispatched to a healthy member at random. This is the path for running a hot-spare backend, scaling out a service horizontally behind a single subdomain, or doing zero-downtime rollouts. Add the load-balancing fields to each pool member’s tunnel definition:

server: tunnel.example.com:4040
auth_token: "your-token"

tunnels:
  a:
    proto: http
    local_port: 3000
    subdomain: pool
    group: web
    group_key: shared-secret-for-this-pool
    health_check:
      type: tcp
      # Optional: when this group goes 0/N healthy, the server POSTs a
      # group_zero_healthy alert to this URL. Per-tenant — independent
      # of any operator-side webhook configured on the edge.
      alert_webhook: "https://hooks.slack.com/services/my-team/..."

Run a second client (on the same or a different host) with local_port: 3001, the same subdomain, and the same (group, group_key). Both clients register as members of the same pool; public connections to pool.tunnel.example.com are dispatched at random across them.

Load balancing requires [load_balancing] enabled = true in the server’s server.toml. When the flag is false (the default), the client’s group / group_key / health_check fields are accepted but ignored — both clients try to register as solo tunnels and the second one fails with subdomain '...' is already in use.

Quick smoke test

End-to-end validation with two backends sharing one subdomain.

Build the client from source

git clone https://github.com/joaoh82/rustunnel
cd rustunnel
cargo build --release -p rustunnel-client

Drop a config that opts into a group

cat > /tmp/lb-test.yml <<'EOF'
server: tunnel.example.com:4040
auth_token: "your-token"

tunnels:
  a:
    proto: http
    local_port: 3000
    subdomain: lbtest
    group: web
    group_key: shared-secret-for-lb-test
    health_check:
      type: tcp
EOF

Start backend A and client A

# Terminal 1 — backend A
python3 -m http.server 3000

# Terminal 2 — client A
./target/release/rustunnel start --config /tmp/lb-test.yml

Start backend B and client B

Use a second config file that’s identical except for local_port: 3001.

# Terminal 3 — backend B
python3 -m http.server 3001

# Terminal 4 — client B
./target/release/rustunnel start --config /tmp/lb-test-b.yml

Hammer the public URL

for i in $(seq 1 50); do
  curl -fsS https://lbtest.tunnel.example.com/ -o /dev/null -w "%{http_code}\n"
done

Both backends should see roughly half of the requests.

Validate failover

Kill one of the local backends (Ctrl-C on its python3 process). The probe loop on that client marks it unhealthy after max_failed × interval_secs seconds; subsequent requests all land on the survivor. Restart the backend — the probe re-registers it as healthy and dispatch distributes again.

For the full reference (config field meanings, behaviour rules, observability series, limitations) see Load Balancing & Health Checks.

`token create` — API token management

Create a new API token via the server’s dashboard REST API. Requires admin credentials.

rustunnel token create --name <label> [options]

Options:

Flag	Default	Description
`--name <label>`	—	Human-readable label for the token (required)
`--server <host:port>`	`localhost:4040`	Dashboard server address
`--admin-token <token>`	—	Admin token for authentication

Example:

rustunnel token create \
  --name "production-server" \
  --server tunnel.example.com:4040 \
  --admin-token admin_secret_here

Output:

Token created:
  id:    f47ac10b-58cc-4372-a567-0e02b2c3d479
  token: rt_live_abc123xyz...
  label: production-server

Copy the token value — it is shown only once. Add it to your config file as auth_token.

Flags Reference

Flag	Commands	Description
`--server <host:port>`	http, tcp	Tunnel server address (bypasses region selection)
`--token <token>`	http, tcp	Auth token (overrides config)
`--subdomain <name>`	http	Requested HTTP subdomain
`--local-host <host>`	http, tcp	Local hostname (default: `localhost`)
`--region <id>`	http, tcp	Region: `eu`, `us`, `ap`, or `auto`. Ignored if `--server` is set.
`--no-reconnect`	http, tcp	Exit on failure instead of reconnecting
`--insecure`	http, tcp	Skip TLS certificate verification
`-c, --config <path>`	start	Config file path
`--name <label>`	token create	Token label (required)
`--admin-token <token>`	token create	Admin token for dashboard API
`--version`	all	Print version and exit
`--help`	all	Print help and exit

setup takes no flags — all input is collected interactively.

Region Selection

rustunnel can connect to multiple edge servers in different geographic regions. The region selection logic follows this priority order:

--server <host:port> — explicit server address always wins; region logic is skipped entirely.
--region <id> — connect directly to the named region without probing.
region: auto (config file or --region auto) — probe all regions in parallel and pick the nearest.
No region preference — use server: from config as-is (backward compatible with self-hosted setups).

Available regions (hosted service)

Region ID	Location	Server
`eu`	Helsinki, FI	`eu.edge.rustunnel.com:4040`
`us`	Hillsboro, OR	`us.edge.rustunnel.com:4040`
`ap`	Singapore	`ap.edge.rustunnel.com:4040`

Auto-select output

When region: auto is active, the client probes all regions by TCP connect time and prints:

  Selecting nearest region… eu 12ms · us 143ms · ap 311ms → eu (Helsinki, FI) 12ms

Unreachable regions time out after 3 seconds and are assigned a 10-second penalty so they never win the selection.

Region list refresh

The region list is cached at ~/.rustunnel/regions.json for 24 hours. On expiry the client fetches a fresh list from GET https://<host>:8443/api/regions; if that fails it falls back to the hardcoded list compiled into the binary.

Reconnection Behavior

By default, rustunnel reconnects automatically when the connection drops. The retry delay follows an exponential backoff schedule:

Attempt	Delay
1	~1 s
2	~2 s
3	~4 s
4	~8 s
…	…
n≥6	~60 s (max)

Each delay has ±20% random jitter to prevent thundering-herd reconnects when a server restarts.

  Reconnecting in 2.3s (attempt 2)…
  Reconnecting in 5.1s (attempt 3)…

Fatal errors (no reconnect)

The following errors cause an immediate exit — retrying would not help:

Auth failed — invalid or revoked token. Fix: create a new token at rustunnel.com (Dashboard → API Keys) and update your config.
Config error — missing required fields. Fix: check your ~/.rustunnel/config.yml.

Disabling reconnect

Use --no-reconnect for scripting, CI, or when you want manual control:

rustunnel http 3000 --no-reconnect || echo "Tunnel exited"

Terminal Output

Connecting spinner

While establishing the connection a spinner is shown:

⠙ Connecting to tunnel server…
⠹ Authenticating…
⠸ Registering tunnels…

Startup box

Once all tunnels are registered, a bordered box appears:

╭────────────────────────────────────────────────────────────╮
│                         rustunnel                          │
├────────────────────────────────────────────────────────────┤
│   HTTP [myapp] → localhost:3000                            │
│   https://myapp.tunnel.example.com                        │
│   TCP  [ssh]   → localhost:22                             │
│   tcp://tunnel.example.com:34521                          │
╰────────────────────────────────────────────────────────────╯

  ✓ Tunnels active. Press Ctrl-C to quit.

Color coding:

Protocol label — bold yellow
Tunnel name — dim
Public URL — bold green
Border — cyan

Graceful shutdown

Press Ctrl-C to cleanly close the tunnel and exit. The control WebSocket is closed before the process exits.

Environment Variables

Variable	Description
`RUST_LOG`	Log level filter (e.g. `debug`, `info`, `warn`, `rustunnel=debug`). Default: `warn`.

Examples:

# Enable debug logging for all crates
RUST_LOG=debug rustunnel http 3000

# Enable debug only for rustunnel internals
RUST_LOG=rustunnel=debug rustunnel http 3000

# Quiet mode (errors only)
RUST_LOG=error rustunnel http 3000

Log output goes to stderr. Normal tunnel output (startup box, reconnect messages) goes to stdout.

Error Reference

Error	Cause	Fix
`config error: server address is required`	No `--server` flag and no config file	Add `server:` to `~/.rustunnel/config.yml` or pass `--server`
`auth failed: <message>`	Token invalid or revoked	Create a new token at rustunnel.com (Dashboard → API Keys) or with `rustunnel token create` for self-hosted setups
`tunnel error: <message>`	Subdomain already in use or server limit reached	Use a different `--subdomain` or wait
`connection error: control WS: …`	Can’t reach the server	Check network, firewall, and server address
`connection error: heartbeat timeout`	Server stopped responding to pings	Transient — reconnect loop will retry
`connection error: timeout waiting for server response`	Auth/registration timed out (10 s)	Check server health; may be overloaded
`no tunnels defined in config file`	`rustunnel start` with an empty `tunnels:` map	Add at least one tunnel to the config

Troubleshooting

Tunnel connects but requests don’t arrive

Verify your local service is running and listening: curl http://localhost:<port>
Check --local-host if forwarding to a non-localhost address

Certificate verification failed

If your server uses a self-signed certificate (common for local/staging environments), use --insecure:

rustunnel http 3000 --insecure

Never use --insecure in production — it disables all TLS certificate checks.

Subdomain already taken

The server returns tunnel error: subdomain already in use. Either:

Omit --subdomain to get an auto-assigned subdomain, or
Choose a different name: --subdomain myapp-dev

Debugging connection issues

Enable verbose logging to see full protocol traces:

RUST_LOG=debug rustunnel http 3000 2>&1 | tee rustunnel.log

Key log messages to look for:

Message	Meaning
`authenticated session_id=...`	Auth succeeded
`tunnel registered public_url=...`	Tunnel is active
`data WebSocket connected`	Data plane is ready
`new connection from server conn_id=...`	Incoming proxied request
`yamux data conn error`	Data-plane transport error
`heartbeat timeout`	Server stopped responding — will reconnect

Multiple tunnels on the same server

Use rustunnel start with a config file to open all tunnels over a single control connection:

server: tunnel.example.com:9000
auth_token: rt_live_abc123

tunnels:
  frontend:
    proto: http
    local_port: 3000
    subdomain: app
  backend:
    proto: http
    local_port: 8080
    subdomain: api
  metrics:
    proto: tcp
    local_port: 9090

rustunnel start

Getting started

Guides

Reference

rustunnel CLI Client Guide — every flag, command, and config option

Installation

From source (recommended)

Verify

Quick Start

Configuration File

Full example

Field reference

Commands

`setup` — Interactive config wizard

`http` — HTTP tunnel

`tcp` — TCP tunnel

`start` — Multi-tunnel mode

Multiple backends (load balancing)

Quick smoke test

`token create` — API token management

Flags Reference

Region Selection

Available regions (hosted service)

Auto-select output

Region list refresh

Reconnection Behavior

Fatal errors (no reconnect)

Disabling reconnect

Terminal Output

Connecting spinner

Startup box

Graceful shutdown

Environment Variables

Error Reference

Troubleshooting

Tunnel connects but requests don’t arrive

Certificate verification failed

Subdomain already taken

Debugging connection issues

Multiple tunnels on the same server

Getting started

Guides

Reference

Documentation Index

​Installation

​From source (recommended)

​Verify

​Quick Start

​Configuration File

​Full example

​Field reference

​Commands

​setup — Interactive config wizard

​http — HTTP tunnel

​tcp — TCP tunnel

​start — Multi-tunnel mode

​Multiple backends (load balancing)

​Quick smoke test

​token create — API token management

​Flags Reference

​Region Selection

​Available regions (hosted service)

​Auto-select output

​Region list refresh

​Reconnection Behavior

​Fatal errors (no reconnect)

​Disabling reconnect

​Terminal Output

​Connecting spinner

​Startup box

​Graceful shutdown

​Environment Variables

​Error Reference

​Troubleshooting

​Tunnel connects but requests don’t arrive

​Certificate verification failed

​Subdomain already taken

​Debugging connection issues

​Multiple tunnels on the same server

Installation

From source (recommended)

Verify

Quick Start

Configuration File

Full example

Field reference

Commands

`setup` — Interactive config wizard

`http` — HTTP tunnel

`tcp` — TCP tunnel

`start` — Multi-tunnel mode

Multiple backends (load balancing)

Quick smoke test

`token create` — API token management

Flags Reference

Region Selection

Available regions (hosted service)

Auto-select output

Region list refresh

Reconnection Behavior

Fatal errors (no reconnect)

Disabling reconnect

Terminal Output

Connecting spinner

Startup box

Graceful shutdown

Environment Variables

Error Reference

Troubleshooting

Tunnel connects but requests don’t arrive

Certificate verification failed

Subdomain already taken

Debugging connection issues

Multiple tunnels on the same server