Due: May 2, 2022

In this HW, we will learn about how quickly DNS information can propagate through the Internet.

We will identify at least four vantage points from which we will observe the updates to the DNS records: your laptop, an EC2 instance (separate from the one running your DNS server), two public DNS lookup sites.

1. Learn how to setup your DNS to be the authoritative name server for your domain or sub-domain. This step is needed to make sure your query for an A record goes to your server.
2. From each vantage point, learn how to send a repeated query to the DNS server. You would typically not specify a resolver and let the system defaults handle your DNS queries.
3. Update the A record in your DNS server and note how long it takes for the update to be reflected at your vantage point. Show a graph showing the process.
4. Now change the TTL of your A record in your authoritative server. Does the update appear through your local resolver at exactly the specified TTL? Please show your work with graph/numbers.
5. Compare the latencies until the updates were seen at each vantage point and describe the reasons for those differences if you see the difference.
6. What can we do to make sure DNS updates propagate to all the clients in the Internet other than using a small TTL?
7. Please submit a writeup including all the commands, data collection mechanism, and graphs as relevant.