This project is an implementation of DNS protocol in Node.js and Typescript for educational purposes. If you are interested in learning how DNS works or wondering how you can implement a DNS resolver, name server, or even a networking protocol in Node.js this is the right project for you to study.
This example shows how to create a DNS query for www.instagram.com and send it to Google's public DNS servers.
async function lookup(query: Buffer): Promise<Buffer> {
return new Promise((resolve, reject) => {
const client = dgram.createSocket('udp4');
client.on('error', reject);
client.on('message', (message) => {
client.close();
return resolve(message);
});
client.on('listening', () => {
const address = client.address();
console.log(`Listening on ${address.address}:${address.port}`);
client.send(query, 53, '8.8.8.8', (err, bytes) => {
if (err) {
return reject(err);
}
console.log(`Sent ${bytes} bytes to 8.8.8.8:53`);
});
});
client.bind();
});
}
async function main() {
const builder = new DNSMessageBuilder();
const message = builder
.withHeader(
new DNSMessageHeader({
id: 0x01,
isQuery: true,
recursionDesired: true,
})
)
.withQuestions([
new QuestionEntry({
qname: 'www.instagram.com',
qclass: QCLASS.IN,
qtype: QTYPE.AAAA,
}),
])
.build();
const encoder = new DNSEncoder(message);
const buffer = encoder.encode();
const responseBuffer = await lookup(buffer);
const decoder = new DNSDecoder(responseBuffer);
const responseMessage = decoder.decode();
console.log('Response:', responseMessage);
}
main();The best way to learn how to use this project is to study the tests. You can run the tests by running npm run test.