The socket.setTTL() method is an inbuilt application programming interface of class Socket within dgram module which is used to set or clear the IP_TTL socket option which helps to specify how many IP hops that a packet is allowed to travel through the specified router or gateway.
Syntax:
const socket.setTTL( ttl )
Parameters: This method takes an integer value representing the number of IP hops that a packet is allowed to travel through the specified router or gateway.
Return Value: This method does not return any value.
Example 1: Filename: index.js
// Node.js program to demonstrate the // server.setTTL() method // Importing dgram module const dgram = require( 'dgram' );
// Creating and initializing client // and server socket const client = dgram.createSocket( "udp4" );
const server = dgram.createSocket( "udp4" );
let broadcast_address = 12345; // Catching the message event server.on( "message" , function (msg) {
// Displaying the client message
process.stdout.write( "UDP String: " + msg + "\n" );
// Exiting process
process.exit();
}) .bind(broadcast_address, () => {
// Enable the IP_TTL socket option
// and specifying the number of IP hopes
// by using the setTTL() method
server.setTTL(144);
});
// Client sending message to server client.send( "Hello" , 0, 7, broadcast_address, "localhost" );
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Output:
UDP String: Hello
Example 2: Filename: index.js
// Node.js program to demonstrate the // server.setTTL() method // Importing dgram module const dgram = require( 'dgram' );
// Creating and initializing client // and server socket const client = dgram.createSocket( "udp4" );
const server = dgram.createSocket( "udp4" );
// Catching the message event server.on( "message" , function (msg) {
// Displaying the client message
process.stdout.write( "UDP String: " + msg + "\n" );
// Exiting process
process.exit();
}); // Catching the listening event server.on( 'listening' , () => {
const address = server.address();
console.log(`server listening
${address.address}:${address.port}`);
}); // Binding server with port address server.bind(1234, () => { // Enable the IP_TTL socket option
// and specifying the number of IP hopes
// by using the setTTL() method
server.setTTL(144);
}); // Client sending message to server client.send( "Hello" , 0, 7, 1234, "localhost" );
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Output:
server listening 0.0.0.0:1234 UDP String: Hello
Run the index.js file using the following command:
node index.js
Reference: https://nodejs.org/dist/latest-v12.x/docs/api/dgram.html#dgram_socket_setttl_ttl