Node.js tlsSocket.remoteFamily Property

The tlsSocket.remoteFamily property is an inbuilt application programming interface of class TLSSocket within tls module which is used to return the string representation of the remote IP family.

Syntax:

const tlsSocket.remoteFamily

Return Value: It returns the string representation of the remote IP family.

How to generate a Private key and Public certificate? 

• Private key: Open Notepad and copy and paste the following key: 
   

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

• Now save the filename as a private key.pem
• Public certificate: Open Notepad and copy and paste the following key: 

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

• Now save the filename as public-cert.pem

Example 1: Filename: index.js 

// Node.js program to demonstrate the
// tlsSocket.remoteFamily method
const tls = require('tls'),
    fs = require('fs'),

    // Port and host address for server
    PORT = 1337,
    HOST = '127.0.0.1',
    value = null;

// Private key and public certificate for access
const options = {
    key: fs.readFileSync('private-key.pem'),
    cert: fs.readFileSync('public-cert.pem'),
    rejectUnauthorized: false
};

// Creating and initializing server
const server = tls.createServer(options, function (socket) {

    // Print the data that we received
    socket.on('data', function (data) {
        console.log('\nReceived: %s ',
            data.toString().replace(/(\n)/gm, ""));
    });

    // Stopping the server
    // by using the close() method
    server.close(() => {
        console.log("Server closed successfully");
    });
});

// Start listening on a specific port and address
// by using listen() method
server.listen(PORT, HOST, function () {
    console.log("I'm listening at %s, on port %s", HOST, PORT);
});

// Creating and initializing client
const client = tls.connect(PORT, HOST, options, function () {

    // Getting remote IP Family
    // by using tlsSocket.remoteFamily method
    value = client.remoteFamily;

    client.write("remoteFamily : " + value);

    client.end(() => {
        console.log("Client closed successfully");
    });
});

Run the index.js file using the following command:

node index.js

Output:

I'm listening at 127.0.0.1, on port 1337
Client closed successfully

Received: remoteFamily : IPv4
Server closed successfully

Example 2: Filename: index.js 

// Node.js program to demonstrate the
// tlsSocket.remoteFamily method
const tls = require('tls'),
    fs = require('fs'),

    // Port and host address for server
    PORT = 1337,
    HOST = '127.0.0.1';

// Private key and public certificate for access
const options = {
    key: fs.readFileSync('private-key.pem'),
    cert: fs.readFileSync('public-cert.pem'),
    rejectUnauthorized: false
};

// Creating and initializing server
const server = tls.createServer(options, function (socket) {

    // Getting remote IP Family
    // by using tlsSocket.remoteFamily method
    value = socket.remoteFamily;

    socket.write("remoteFamily : " + value);

    // Stopping the server
    // by using the close() method
    server.close(() => {
        console.log("Server closed successfully")
    });
});

// Start listening on a specific port and address
// by using listen() method
server.listen(PORT, HOST, function () {
    console.log("I'm listening at %s, on port %s", HOST, PORT);
});

// Creating and initializing client
const client = tls.connect(PORT, HOST, options, function () {
    console.log("client is connected");
});

client.on("data", function (data) {

    console.log('Received: %s',
        data.toString().replace(/(\n)/gm, ""));

    // Close the connection after receiving the message
    client.end(() => {
        console.log("client closed successfully")
    });

});

Run the index.js file using the following command:

node index.js

Output:

I'm listening at 127.0.0.1, on port 1337
client is connected
Received: remoteFamily : IPv4
client closed successfully
Server closed successfully

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/tls.html#tls_tlssocket_remotefamily