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1.1.2 • Public • Published

express-ipfilter: A light-weight IP address based filtering system

This package provides easy IP based access control. This can be achieved either by blacklisting certain IPs and whitelisting all others, or whitelisting certain IPs and blacklisting all others.


Recommended installation is with npm. To add express-ipfilter to your project, do:

npm install express-ipfilter

Usage with Express

Blacklisting certain IP addresses, while allowing all other IPs:

// Init dependencies
const express = require('express')
const ipfilter = require('express-ipfilter').IpFilter
// Blacklist the following IPs
const ips = ['']
// Create the server

Whitelisting certain IP addresses, while denying all other IPs:

// Init dependencies
// Init dependencies
const express = require('express')
const ipfilter = require('express-ipfilter').IpFilter
// Whitelist the following IPs
const ips = ['']
// Create the server
app.use(ipfilter(ips, { mode: 'allow' }))
module.exports = app

Using CIDR subnet masks for ranges:

const ips = ['']
// Create the server
app.use(ipfilter(ips, { mode: 'allow' }))
module.exports = app

Using IP ranges:

const ips = [['', '']]
// Create the server
app.use(ipfilter(ips, { mode: 'allow' }))
module.exports = app

Using a function to get Ips:

const ips = function() {
  return ['']
// Create the server
app.use(ipfilter(ips, { mode: 'allow' }))
module.exports = app

Using wildcard ip ranges and nginx forwarding:

  let whitelist_ips = ['10.1.*.*', '123.??.34.8*'] // matches '' and ''
  let clientIp = function(req, res) {
    return req.headers['x-forwarded-for'] ? (req.headers['x-forwarded-for']).split(',')[0] : ""
      id: clientIp,
      forbidden: 'You are not authorized to access this page.',
      strict: false,
      filter: whitelist_ips,

Error Handling

When an IP is denied, an IpDeniedError will be thrown by the middleware. If you do not handle the error, it will cause your app to crash due to an unhandled exception. Here is an example of how to handle the error, which can also be found in the example app:

if (app.get('env') === 'development') {
  app.use((err, req, res, _next) => {
    console.log('Error handler', err)
    if (err instanceof IpDeniedError) {
    } else {
      res.status(err.status || 500)
    res.render('error', {
      message: 'You shall not pass',
      error: err

You will need to require the IpDeniedError type in order to handle it.


Property Description Type Default
mode whether to deny or allow to the IPs provided string deny
log console log actions boolean true
logLevel level of logging (all,deny,allow) string all
excluding routes that should be excluded from ip filtering array []
detectIp define a custom function that takes an Express request object and returns an IP address to test against function built-in detection
trustProxy This setting is implemented using the proxy-addr package. Check the documentation for the trust parameter. boolean, array, string, number, function false

A note on detectIp

If you need to parse an IP address in a way that is not supported by default, you can write your own parser and pass that to ipfilter.

const customDetection = req => {
  var ipAddress
  ipAddress = req.connection.remoteAddress.replace(/\//g, '.')
  return ipAddress
ipfilter(ids, { detectIp: customDetection })


See the CONTRIBUTING.MD document for more information on contributing.

Running Tests

Run tests by using npm test


Moved to GitHub Releases


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npm i express-ipfilter

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