DNS
All interview questions related to DNS
Walk me through the steps when you type a URL into your browser and press enter.
What is the difference between an A record and a CNAME record in DNS, and when would you use each?
What is DNS propagation, and why can DNS record changes take time to be visible globally?
Your services suddenly cannot resolve domain names, breaking connectivity to dependencies. Walk me through your triage.
Canary rollout passed, but a portion of clients hit decommissioned IPs due to stale DNS caches. What do you do?
Your DNS servers are overloaded with suspicious traffic patterns resembling amplification. How do you detect, mitigate, and protect?
Internal and external clients see different DNS answers, causing failures. How do you debug and fix split-horizon issues?