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IP Restrictions

Overview​

IP Restrictions allows you to allow or deny traffic based on the source IP of the connection that was initiated to your ngrok endpoints. You configure the module by defining rules that apply allow or deny actions to 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.

The IP Restrictions module is supported on HTTP, TCP and TLS endpoints.

Quickstart​

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 Configuration File​

tunnels:
  example:
    proto: http
    addr: 80
    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 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 SDK​

import (
    "context"
    "net"

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

func listenIPRestrictions(ctx context.Context) net.Listener {
    listener, _ := 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(),
    )
    return listener
}

Rust SDK​

use ngrok::prelude::*;

async fn start_tunnel() -> 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)
}

Kubernetes Ingress 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

Edges​

IP Restrictions is a supported module for HTTPS, TLS and TCP edges. 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.

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

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​
ParameterDescription
Allow CIDRsA set of IPv4 and IPv6 CIDRs to allow.
Deny CIDRsA set of IPv4 and IPv6 CIDRs to deny.
Edge Configuration​
ParameterDescription
IP Policy IDsA 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​

HTTP​

The following errors are returned on HTTP endpoints.

CodeHTTP StatusError
ERR_NGROK_3205403This error is returned if a connection is disallowed by this module.

TCP + TLS​

For TCP and TLS endpoints, if a connection is disallowed by IP Restrictions then the connection is closed because there is no standardized error reporting at these protocol layers.

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

Limits​

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 \
  --domain 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