IP Restrictions

Overview

The IP Restrictions module allows or denies traffic based on the source IP of the connection that was initiated to your ngrok endpoints. You define rules which allow or deny connections from IPv4 or IPv6 CIDR blocks.

A connection is allowed only if its source IP matches at least one rule with an 'allow' action and does not match any rule with a 'deny' action.

Example Usage

Allow TCP connections from 110.0.0.0/8 and 220.12.0.0/16 but not from 110.2.3.4/32.

Agent CLI

ngrok http 80 --cidr-allow 110.0.0.0/8 --cidr-allow 220.12.0.0/16 --cidr-deny 110.2.3.4/32

Agent Config

tunnels:
  example:
    proto: http
    addr: 80
    ip_restriction:
      allow_cidrs: [110.0.0.0/8, 220.12.0.0/16]
      deny_cidrs: [110.2.3.4/32]

SSH

ssh -R 443:localhost:80 v2@connect.ngrok-agent.com http \
  --cidr-allow 110.0.0.0/8 \
  --cidr-allow 220.12.0.0/16 \
  --cidr-deny 110.2.3.4/32

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.HTTPEndpoint(
			config.WithAllowCIDRString("110.0.0.0/8", "220.12.0.0/16"),
			config.WithDenyCIDRString("110.2.3.4/32"),
		),
		ngrok.WithAuthtokenFromEnv(),
	)
}

Go Package Docs:

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

Javascript

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

(async function () {
	const listener = await ngrok.forward({
		addr: 8080,
		authtoken_from_env: true,
		ip_restriction_allow_cidrs: ["110.0.0.0/8", "220.12.0.0/16"],
		ip_restriction_deny_cidrs: "110.2.3.4/32",
	});

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

Javascript SDK Docs:

• https://ngrok.github.io/ngrok-javascript/interfaces/Config.html#ip_restriction_allow_cidrs
• https://ngrok.github.io/ngrok-javascript/interfaces/Config.html#ip_restriction_deny_cidrs
• https://ngrok.github.io/ngrok-javascript/classes/HttpListenerBuilder.html#allowCidr
• https://ngrok.github.io/ngrok-javascript/classes/HttpListenerBuilder.html#denyCidr

Python

import ngrok

listener = ngrok.forward("localhost:8080", authtoken_from_env=True,
    ip_restriction_allow_cidrs=["110.0.0.0/8", "220.12.0.0/16"],
    ip_restriction_deny_cidrs="110.2.3.4/32")

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

Python SDK Docs:

• https://ngrok.github.io/ngrok-python/http_listener_builder.html#ngrok.HttpListenerBuilder.allow_cidr
• https://ngrok.github.io/ngrok-python/http_listener_builder.html#ngrok.HttpListenerBuilder.deny_cidr
• 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
        .http_endpoint()
        .allow_cidr("110.0.0.0/8"),
        .allow_cidr("220.12.0.0/16"),
        .deny_cidr("110.2.3.4/32"),
        .listen()
        .await?;
    println!("Listening on URL: {:?}", tun.url());
    Ok(tun)
}

Rust Crate Docs:

• https://docs.rs/ngrok/latest/ngrok/config/struct.HttpTunnelBuilder.html#method.allow_cidr
• https://docs.rs/ngrok/latest/ngrok/config/struct.HttpTunnelBuilder.html#method.deny_cidr

Kubernetes Controller

kind: IPPolicy
apiVersion: ingress.k8s.ngrok.com/v1alpha1
metadata:
  name: policy-1
spec:
  description: "My Trusted IPs"
  rules:
    - action: "allow"
      cidr: "110.0.0.0/8"
    - action: "allow"
      cidr: "220.12.0.0/16"
    - action: "deny"
      cidr: "110.2.3.4/32"
---
kind: NgrokModuleSet
apiVersion: ingress.k8s.ngrok.com/v1alpha1
metadata:
  name: ngrok-module-set
modules:
  ipRestriction:
    policies:
      - "policy-1" # Reference to the `ippolicy.ingress.k8s.ngrok.com` Custom Resource above
      - "ipp_1234567890" # Reference to an IP Policy by its ngrok API ID
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    k8s.ngrok.com/modules: ngrok-module-set
spec:
  ingressClassName: ngrok
  rules:
    - host: your-domain.ngrok.app
      http:
        paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: example-service
                port:
                  number: 80

Behavior

Rule Evaluation

A connection is allowed only if its source IP matches at least one rule with an 'allow' action and does not match any rule with a 'deny' action.

When using Edges and the Kubernetes Ingress Controller, if the IP Restrictions module references multiple IP Policies, then the rules of all referenced IP Policies are unioned together for evaluation.

IPv6

ngrok supports IPv6 addresses for all IP rules. You may use standard abbreviated notations.

ngrok http 80 --allow-cidr "::/0" --deny-cidr "2600:1f16:d83:1202::6e:2/128"

Don't forget to create IPv6 rules. It's easy to test only with IPv4 and then suddenly things don't work when your software starts using IPv6 because you've forgotten to create rules to allow traffic from IPv6 addresses.

Forwarded-For

The IP Restrictions always evaluates its rules against the layer 4 source IP of a connection. HTTP headers like forwarded-for are never consulted by this module.

Reference

Configuration

Agent Configuration

Parameter	Description
Allow CIDRs	A set of IPv4 and IPv6 CIDRs to allow.
Deny CIDRs	A set of IPv4 and IPv6 CIDRs to deny.

Edge Configuration

Parameter	Description
IP Policy IDs	A set of IP policies that will be used to check if a source IP is allowed access. See the HTTPS Edge IP Restrictions Module API Resource for additional details.

Upstream Headers

This module does not add any upstream headers.

Errors

The following errors are returned on HTTP endpoints.

Code	HTTP Status	Error
ERR_NGROK_3205	403	This error is returned if a connection is disallowed by this module.

Events

When the IP Restrictions module is enforced, it populates the following fields in both the http_request_complete.v0 and the tcp_connection_closed.v0 events.

Fields
ip_policy.decision

Edges

IP Restrictions is an HTTPS Edge module which can be applied to Routes.

When using IP Restrictions via Edges, you specify a set of references to one or more IP Policy objects, each of which contains a list of IP Policy Rule objects.

IP Restrictions and the IP Policy and IP Policy Rule objects they reference can be configured via the ngrok dashboard or API.

• HTTPS Edge IP Restrictions Module API Resource
• IP Policy API Resource
• IP Policy Rule API Resource

Pricing

This module is available on the Pro and Enterprise plans.

Try it out

First, grab your IPv4 and IPv6 addresses:

curl -4 icanhazip.com
curl -6 icanhazip.com

Then run ngrok with IP Restrictions with the IPv4 and IPv6 addresses you got in the previous step:

ngrok http 80 \
  --url your-domain.ngrok.app \
  --allow-cidr 2600:8c00::a03c:91ee:fe69:9695/32 \
  --allow-cidr 78.227.75.230/32

Then make requests to your ngrok domain using the -4 and -6 flags to test both IPv4 and IPv6:

curl -4 https://your-domain.ngrok.app
curl -6 https://your-domain.ngrok.app