IP Restrictor

Easily allow or block internal IPs in Node.js and Express apps. A simple middleware for IP filtering and network security.

📦 Installation

Install via npm

1npm i ip-restrictor

Install via yarn

1yarn add ip-restrictor

🚀 Usage

Express Middleware

1const express = require("express");
2const { allowOnly, blockOnly, isInternalIP, getClientIP } = require("ip-restrictor");
3
4const app = express();
5
6// Only allow specific internal IPs
7app.use((req, res, next) => {
8    const clientIP = getClientIP(req);
9    console.log(`Checking allowOnly middleware for IP: ${clientIP}`);
10    next(); // Call the original allowOnly middleware
11}, allowOnly(["192.168.1.100", "10.0.0.5"]));
12
13// Block specific internal IPs
14app.use((req, res, next) => {
15    const clientIP = getClientIP(req);
16    console.log(`Checking blockOnly middleware for IP: ${clientIP}`);
17    next(); // Call the original blockOnly middleware
18}, blockOnly(["192.168.1.200"]));
19
20app.get("/", (req, res) => {
21    const clientIP = getClientIP(req);
22    res.send(`Your IP: ${clientIP} - Internal: ${isInternalIP(clientIP)}`);
23});
24
25app.listen(3000, () => console.log("Server running on port 3000"));

Standalone Usage (Without Express)

1const { allowOnlyStandalone, blockOnlyStandalone } = require("ip-restrictor");
2
3const myIP = "192.168.1.100";
4
5if (allowOnlyStandalone(["192.168.1.100"], myIP)) {
6    console.log("Access granted.");
7} else {
8    console.log("Access denied.");
9}
10
11if (blockOnlyStandalone(["192.168.1.200"], myIP)) {
12    console.log("Not blocked, you may proceed.");
13} else {
14    console.log("You are blocked.");
15}

Standalone Usage (Without Express) 2.0

1const { allowOnlyStandalone, blockOnlyStandalone } = require("ip-restrictor");
2
3const testIPs = [
4    { allowed: ["192.168.1.100"], blocked: ["192.168.1.200"], myIP: "192.168.1.100" },
5    { allowed: ["192.168.1.101"], blocked: ["192.168.1.200"], myIP: "192.168.1.100" },
6    { allowed: [], blocked: ["192.168.1.100"], myIP: "192.168.1.100" },
7    { allowed: ["192.168.1.100"], blocked: [], myIP: "192.168.1.200" },
8];
9
10testIPs.forEach(({ allowed, blocked, myIP }, index) => {
11    console.log(`Test Case ${index + 1}`);
12    console.log(`Allowed: ${allowed}, Blocked: ${blocked}, MyIP: ${myIP}`);
13    console.log(
14        allowOnlyStandalone(allowed, myIP)
15            ? "Access granted."
16            : "Access denied."
17    );
18    console.log(
19        blockOnlyStandalone(blocked, myIP)
20            ? "Not blocked, you may proceed."
21            : "You are blocked."
22    );
23    console.log("-----");
24});

📖 API Reference

Function	Type	Parameters	Returns	Description
allowOnly	Middleware	allowedIPs: string[]	Express Middleware	Allows only specific IPs to access the server. Blocks all others.
blockOnly	Middleware	blockedIPs: string[]	Express Middleware	Blocks specific IPs while allowing all others.
allowOnlyStandalone	Function	allowedIPs: string[], ip: string	true / false	Returns true if ip is in allowedIPs, otherwise false.
blockOnlyStandalone	Function	blockedIPs: string[], ip: string	true / false	Returns false if ip is in blockedIPs, otherwise true.
isInternalIP	Function	ip: string	true / false	Checks if the given IP is part of a private/internal network.
getClientIP	Function	req: Request	string (IP)	Extracts the client’s IP from an Express request object.