dns-stub-resolver

This is a very basic DNS stub resolver - essentially a simple DNS client. It can only take a domain name and get the IPv4 address. This is how to use it:

git clone [email protected]:BenLorantfy/dns-stub-resolver
cd dns-stub-resolver
npm install
./node_modules/.bin/ts-node ./src/main.ts [domain_name]

Here is some example output for a few domains:

Ben-Lorantfys-MacBook-Pro:dns_resolver ben$ ./node_modules/.bin/ts-node ./src/main.ts google.com
172.217.165.14

Ben-Lorantfys-MacBook-Pro:dns_resolver ben$ ./node_modules/.bin/ts-node ./src/main.ts benlorantfy.com
76.76.21.21

Ben-Lorantfys-MacBook-Pro:dns_resolver ben$ ./node_modules/.bin/ts-node ./src/main.ts twitter.com
104.244.42.129

You can also see the help page by running:

./node_modules/.bin/ts-node ./src/main.ts --help

This project was mostly to learn more about how DNS works. I learned a lot from this guide but I wrote the code without really looking at the rust version in this guide.

I may add support for more record types in the future, and possibly implement a recursive resolver so it doesn't have to depend on google's public DNS server.

What does this do?

This program does the following:

1. Takes a domain name as input
2. Constructs a DNS query packet. Basically a string of bytes representing a small DNS payload.
3. Sends the DNS query packet over UDP to google's public DNS server
4. Recieves the DNS response packet from google
5. Parses the DNS response packet and finds the IP address
6. Outputs the IP address to stdout