Port Forward Configuration

Expose local services through the mesh network. Services register with a routing key via endpoints, and any agent can create listeners to access them locally - a lightweight service discovery pattern.

See Port Forwarding Usage for the service discovery pattern and use cases.

Quick setup:

# On agent with the service (endpoint side):
forward:
  endpoints:
    - key: "my-web"
      target: "localhost:80"

# On agents where clients connect (listener side):
forward:
  listeners:
    - key: "my-web"
      address: ":8080"

Configuration

forward:
  # Endpoints - where your services run
  endpoints:
    - key: "web-server"           # Routing key (advertised to mesh)
      target: "localhost:3000"     # Local service address
    - key: "internal-api"
      target: "192.168.1.10:8080"

  # Listeners - where remote clients connect
  listeners:
    - key: "web-server"           # Must match an endpoint key
      address: ":8080"            # Bind address for incoming connections
      max_connections: 100        # Optional connection limit

Endpoints

Endpoints define services that can be reached through the mesh. Configure these on agents that have access to the target service.

forward:
  endpoints:
    - key: "tools"
      target: "localhost:80"

Options

Option	Type	Required	Description
key	string	Yes	Unique routing key advertised to the mesh. Other agents use this key to reach this endpoint.
target	string	Yes	Fixed destination in host:port format. Connections are forwarded here.

Routing Key Guidelines

• Use descriptive names that reflect the service purpose
• Keys are case-sensitive
• Must be unique within the mesh (duplicate keys cause routing conflicts)
• Examples: "config-server", "dev-api", "backup-sync"

Listeners

Listeners accept incoming connections from remote clients and route them through the mesh to matching endpoints.

forward:
  listeners:
    - key: "tools"
      address: "127.0.0.1:8080"
      max_connections: 50

Options

Option	Type	Required	Default	Description
key	string	Yes	-	Routing key to look up. Must match an endpoint's key somewhere in the mesh.
address	string	Yes	-	Local bind address in host:port or :port format.
max_connections	int	No	0 (unlimited)	Maximum concurrent connections through this listener.

Bind Address Guidelines

• 127.0.0.1:8080 - Localhost only (more secure)
• 0.0.0.0:8080 or :8080 - All interfaces (required for network access)
• 192.168.1.10:8080 - Specific interface only

Dynamic Management

Both endpoints and listeners can be added, removed, and listed at runtime without editing config.yaml. Runtime changes persist across restarts when agent.data_dir is configured; otherwise they remain ephemeral. See Dynamic Config Persistence for the journal format and guarantees.

Endpoints (CLI: muti-metroo forward endpoint add/remove/list, HTTP: POST /forward/endpoints/manage):

# Register a routing key -> target on the exit side
muti-metroo forward endpoint add web-server 127.0.0.1:3000

# ... or on a remote agent
muti-metroo forward endpoint add web-server 127.0.0.1:3000 -t abc123

muti-metroo forward endpoint list
muti-metroo forward endpoint remove web-server

Listeners (CLI: muti-metroo forward add/remove/list, HTTP: POST /forward/manage):

muti-metroo forward add web-server :9090
muti-metroo forward list
muti-metroo forward remove web-server

Config-declared endpoints and listeners are protected from runtime mutation; list flags each entry as static or dynamic so you can tell them apart. When management-key encryption is enabled, agents without the decrypt capability reject mutation requests with HTTP 403.

Route Advertisement

Endpoint routes propagate through the mesh using flood routing:

• Automatic: Routes advertised every routing.advertise_interval (default 2 minutes)
• Manual trigger: POST /routes/advertise on the endpoint agent's HTTP API

# Trigger immediate route advertisement
curl -X POST http://localhost:8080/routes/advertise

Examples

Configuration Distribution Server

Serve configuration files from headquarters to remote sites:

# Central server - runs HTTP server on port 8000
forward:
  endpoints:
    - key: "config-server"
      target: "localhost:8000"

# Remote site agents - accept connections on port 8080
forward:
  listeners:
    - key: "config-server"
      address: "127.0.0.1:8080"
      max_connections: 50

Internal API Access

Make internal services accessible from remote offices:

# Headquarters - API server on port 3000
forward:
  endpoints:
    - key: "internal-api"
      target: "localhost:3000"

# Branch office agents - expose API locally
forward:
  listeners:
    - key: "internal-api"
      address: "127.0.0.1:3000"

Multiple Services

Expose several services with different keys:

forward:
  endpoints:
    - key: "http-tools"
      target: "localhost:80"
    - key: "smb-share"
      target: "localhost:445"
    - key: "ssh-jump"
      target: "localhost:22"

High Availability (Multiple Listeners)

Deploy the same listener on multiple agents for redundancy:

# Agent 1
forward:
  listeners:
    - key: "tools"
      address: ":8080"

# Agent 2 (same key)
forward:
  listeners:
    - key: "tools"
      address: ":8080"

Clients can connect to whichever agent is nearest.

Troubleshooting

Error	Cause	Solution
"forward key not found"	No endpoint with matching key	Verify endpoint is configured and agent is connected to mesh
Connection timeout	Route not propagated yet	Wait for advertise_interval or trigger POST /routes/advertise
Connection refused	Target service not running	Verify service is listening on the endpoint's target port
Listener bind failed	Port already in use	Choose a different port or stop conflicting service

Verify Routes

Check if a forward route exists:

curl http://localhost:8080/healthz | jq '.forward_routes'

Security Considerations

• Use unique keys: Predictable keys could be guessed by unauthorized users
• Bind to localhost: Use 127.0.0.1 when external network access isn't needed
• Set connection limits: Prevent resource exhaustion
• Firewall integration: Allow listener ports through host firewall only where needed

Related

• Features - Port Forwarding - Feature overview
• Concepts - Routing - How routes propagate