TCP Endpoints

Overview

ngrok's TCP endpoints enable you to deliver any network service with a TCP-based protocol. For example, it is commonly used to establish connectivity for:

• Remote access protocols like SSH, VNC and RDP
• Databases like MySQL, Postgres, MSSQL and SQLite
• IoT protocols like MQTT
• Gaming servers like Minecraft

If the service you are delivering uses TLS, prefer to create a TLS Endpoint.

Because the TCP protocol is low-level, ngrok offers very little functionality to manipulate TCP traffic beyond restricting access via IP Restrictions.

Example Usage

Random Address

Listen on a random TCP address.

Agent CLI

ngrok tcp 22

Agent Config

tunnels:
  example:
    proto: tcp
    addr: 22

SSH

ssh -R 0:localhost:22 v2@connect.ngrok-agent.com tcp

Go

import (
	"context"
	"net"

	"golang.ngrok.com/ngrok"
	"golang.ngrok.com/ngrok/config"
)

func ngrokListener(ctx context.Context) (net.Listener, error) {
	return ngrok.Listen(ctx,
		config.TCPEndpoint(),
		ngrok.WithAuthtokenFromEnv(),
	)
}

Go Package Docs:

• https://pkg.go.dev/golang.ngrok.com/ngrok/config#TCPEndpoint
• https://pkg.go.dev/golang.ngrok.com/ngrok/config#TCPEndpointOption

Javascript

const ngrok = require("@ngrok/ngrok");

(async function () {
	const listener = await ngrok.forward({
		addr: 8080,
		authtoken_from_env: true,
		proto: "tcp",
	});

	console.log(`Ingress established at: ${listener.url()}`);
})();

Javascript SDK Docs

• https://ngrok.github.io/ngrok-javascript/classes/TcpListenerBuilder.html
• https://ngrok.github.io/ngrok-javascript/classes/Session.html#tcpEndpoint
• https://ngrok.github.io/ngrok-javascript/interfaces/Config.html#proto

Python

import ngrok

listener = ngrok.forward("localhost:8080", authtoken_from_env=True,
    proto="tcp")

print(f"Ingress established at: {listener.url()}");

Python SDK Docs:

• https://ngrok.github.io/ngrok-python/module.html#ngrok.connect
• https://ngrok.github.io/ngrok-python/tcp_listener_builder.html#ngrok.TcpListenerBuilder.listen_and_forward

Rust

use ngrok::prelude::*;

async fn listen_ngrok() -> anyhow::Result<impl Tunnel> {
    let sess = ngrok::Session::builder()
        .authtoken_from_env()
        .connect()
        .await?;

    let tun = sess
        .tcp_endpoint()
        .listen()
        .await?;

    println!("Listening on URL: {:?}", tun.url());

    Ok(tun)
}

Rust Crate Docs

• https://docs.rs/ngrok/latest/ngrok/session/struct.Session.html#method.tcp_endpoint
• https://docs.rs/ngrok/latest/ngrok/config/struct.TcpTunnelBuilder.html

Kubernetes Controller

info

TCP Endpoints are not supported via the Kubernetes Ingress Controller

Fixed Address

Listen on the TCP Address 1.tcp.eu.ngrok.io:12345. You must create this TCP address ahead of time, see TCP Addresses.

Agent CLI

ngrok tcp 3389 --remote-addr 1.tcp.eu.ngrok.io:12345

Agent Config

tunnels:
  example:
    proto: tcp
    addr: 3389
    remote_addr: 1.tcp.eu.ngrok.io:12345

SSH

ssh -R 1.tcp.eu.ngrok.io:12345:localhost:3389 connect.eu.ngrok-agent.com tcp

Go

import (
	"context"
	"net"

	"golang.ngrok.com/ngrok"
	"golang.ngrok.com/ngrok/config"
)

func ngrokListener(ctx context.Context) (net.Listener, error) {
	return ngrok.Listen(ctx,
		config.TCPEndpoint(
			config.WithRemoteAddr("1.tcp.ngrok.io:12345"),
		),
		ngrok.WithRegion("eu"),
		ngrok.WithAuthtokenFromEnv(),
	)
}

Go Package Docs:

• https://pkg.go.dev/golang.ngrok.com/ngrok/config#WithRemoteAddr

Javascript

const ngrok = require("@ngrok/ngrok");

(async function () {
	const listener = await ngrok.forward({
		addr: 8080,
		authtoken_from_env: true,
		proto: "tcp",
		remote_addr: "1.tcp.eu.ngrok.io:12345",
	});

	console.log(`Ingress established at: ${listener.url()}`);
})();

Javascript SDK Docs:

• https://ngrok.github.io/ngrok-javascript/interfaces/Config.html#remote_addr
• https://ngrok.github.io/ngrok-javascript/classes/TcpListenerBuilder.html#remoteAddr

Python

import ngrok

listener = ngrok.forward("localhost:8080", authtoken_from_env=True,
    proto="tcp",
    remote_addr="1.tcp.eu.ngrok.io:12345")

print(f"Ingress established at: {listener.url()}");

Python SDK Docs:

• https://ngrok.github.io/ngrok-python/tcp_listener_builder.html#ngrok.TcpListenerBuilder.remote_addr
• https://ngrok.github.io/ngrok-python/index.html#full-configuration

Rust

use ngrok::prelude::*;

async fn listen_ngrok() -> anyhow::Result<impl Tunnel> {
    let sess = ngrok::Session::builder()
        .authtoken_from_env()
        .connect()
        .await?;

    let tun = sess
        .tcp_endpoint()
        .remote_addr("1.tcp.eu.ngrok.io:12345")
        .listen()
        .await?;

    println!("Listening on URL: {:?}", tun.url());

    Ok(tun)
}

Rust Crate Docs:

• https://docs.rs/ngrok/latest/ngrok/config/struct.TcpTunnelBuilder.html#method.remote_addr

Kubernetes Controller

info

TCP Endpoints are not supported via the Kubernetes Ingress Controller

Forward to non-local service

Forward to a non-local Postgres instance listening on your network at 192.168.1.2:5432.

Agent CLI

ngrok tcp 192.168.1.2:5432

Agent Config

tunnels:
  example:
    proto: tcp
    addr: 192.168.1.2:5432

SSH

ssh -R 0:192.168.1.2:5432 v2@connect.ngrok-agent.com tcp

Go

info

Forwarding to a non-local address is not supported by the Go SDK

Javascript

const ngrok = require("@ngrok/ngrok");

(async function () {
	const listener = await ngrok.forward({
		addr: "192.168.1.2:5432",
		authtoken_from_env: true,
		proto: "tcp",
	});

	console.log(`Ingress established at: ${listener.url()}`);
})();

Javascript SDK Docs:

• https://ngrok.github.io/ngrok-javascript/interfaces/Config.html#addr
• https://ngrok.github.io/ngrok-javascript/classes/TcpListenerBuilder.html#listenAndForward

Python

import ngrok

listener = ngrok.forward("192.168.1.2:5432", authtoken_from_env=True,
    proto="tcp")

print(f"Ingress established at: {listener.url()}");

Python SDK Docs:

• https://ngrok.github.io/ngrok-python/module.html#ngrok.connect
• https://ngrok.github.io/ngrok-python/tcp_listener_builder.html#ngrok.TcpListenerBuilder.listen_and_forward

Rust

info

Forwarding to a non-local address is not supported by the Rust SDK

Kubernetes Controller

info

TCP Endpoints are not supported via the Kubernetes Ingress Controller

PROXY Protocol

Add a PROXY protocol header on connection to your upstream service. This sends connection information like the original client IP address to your upstream service.

Agent CLI

ngrok tcp 22 --proxy-proto=2

Agent Config

tunnels:
  example:
    proto: tcp
    addr: 22
    proxy_proto: 2

SSH

info

PROXY proto is not support via SSH.

Go

import (
	"context"
	"net"

	"golang.ngrok.com/ngrok"
	"golang.ngrok.com/ngrok/config"
)

func ngrokListener(ctx context.Context) (net.Listener, error) {
	return ngrok.Listen(ctx,
		config.TCPEndpoint(
			config.WithProxyProto(2),
		),
		ngrok.WithAuthtokenFromEnv(),
	)
}

Go Package Docs:

• https://pkg.go.dev/golang.ngrok.com/ngrok/config#WithProxyProto

Javascript

const ngrok = require("@ngrok/ngrok");

(async function () {
	const listener = await ngrok.forward({
		addr: 8080,
		authtoken_from_env: true,
		proto: "tcp",
		proxy_proto: "2",
	});

	console.log(`Ingress established at: ${listener.url()}`);
})();

Javascript SDK Docs:

• https://ngrok.github.io/ngrok-javascript/interfaces/Config.html#proxy_proto
• https://ngrok.github.io/ngrok-javascript/classes/TcpListenerBuilder.html#proxyProto

Python

import ngrok

listener = ngrok.forward("localhost:8080", authtoken_from_env=True,
    proto="tcp",
    proxy_proto="2")

print(f"Ingress established at: {listener.url()}");

Python SDK Docs:

• https://ngrok.github.io/ngrok-python/tcp_listener_builder.html#ngrok.TcpListenerBuilder.proxy_proto
• https://ngrok.github.io/ngrok-python/index.html#full-configuration

Rust

use ngrok::prelude::*;

async fn listen_ngrok() -> anyhow::Result<impl Tunnel> {
    let sess = ngrok::Session::builder()
        .authtoken_from_env()
        .connect()
        .await?;

    let tun = sess
        .tcp_endpoint()
        .proxy_proto(ProxyProto::V2)
        .listen()
        .await?;

    println!("Listening on URL: {:?}", tun.url());

    Ok(tun)
}

Rust Crate Docs:

• https://docs.rs/ngrok/latest/ngrok/config/struct.TcpTunnelBuilder.html#method.proxy_proto

Kubernetes Controller

info

TCP Endpoints are not supported via the Kubernetes Ingress Controller

Behavior

Endpoints

When your TCP endpoint is online, it will be available as an Endpoint resource. Endpoints have URLs, but there is no standard scheme for TCP URLs so ngrok renders them as tcp://.

TCP Addresses

If you would like your TCP endpoints to be fixed, you must first provision a TCP address. TCP Addresses include a hostname and port component and look like 1.tcp.ngrok.io:12345. When you provision a TCP address, a random address will be assigned to you. If you delete a TCP address, there is no way to provision the same one again. TCP addresses may be managed via the dashboard and via API.

• Provision a TCP Address via the ngrok Dashboard
• Provision a TCP Address via API

Customization

TCP Addresses are assigned randomly on an ngrok-controlled hostname with a randomly-assigned port. You may not choose the hostname and you may not select the port.

You may, however, simulate a customized hostname by creating a CNAME record to the hostname of your assigned TCP address. If you do so, be aware that all ports on that hostname, even those provisioned to other accounts will then be available on your domain.

Reference

Edges

Edges enable you to centrally manage your endpoints' Module configurations in the ngrok dashboard or API instead of defining them via an Agent or Agent SDK.

• A TCP Edge is attached to one or more TCP Addresses. For each TCP Address, it creates a TCP Endpoint that it listens for traffic on.
• When a TCP Address is associated with a TCP Edge, agents may no longer start endpoints on that TCP Address. You can always detach a TCP Address from your Edge if you want to create Endpoints on it from an Agent or Agent SDK.
• Modules on a TCP Edge are attached directly to the edge itself. There are no Routes.
• When you create a TCP Edge via the dashboard, it will automatically create a new TCP Address assign it to your Edge.
• When you create a TCP Edge via the dashboard, it will automatically create a tunnel group backend with a unique label.

Modules

Use modules to modify the behavior of traffic flowing through your endpoints.

Module	Description
IP Restrictions	Allow or deny traffic based on the source IP of connections

Observability

Use ngrok's events system to capture logs of tcp connections to your endpoints.

When TCP connections to your endpoints are closed, tcp_connection_closed.v0 events are published.

Errors

If an error is encountered while handling TCP connections to your endpoints for any reason (e.g. no available backends, module rejected a connection or internal server error), the connection will be closed. Because of the low-level nature of the TCP protocol, there is no mechanism used to transmit information about what error code was encountered.

You can use the use the observability primitives to understand the error handling behavior of a connection.

Pricing

TCP endpoints are available on all plans.

Fixed TCP Addresses are available on the Pro and Enterprise plans.