Question 1

What is DNS?

Accepted Answer

DNS (Domain Name System) is the internet's phone book — it translates human-readable domain names (google.com) into IP addresses (142.250.80.46) that computers use to communicate. DNS uses a hierarchical distributed database with different record types for different purposes.

Question 2

What are the different DNS record types?

Accepted Answer

A: IPv4 address. AAAA: IPv6 address. MX: Mail server (with priority). NS: Authoritative nameservers. TXT: Text data (used for SPF, DKIM, domain verification). CNAME: Alias to another domain. SOA: Zone authority info. PTR: Reverse lookup (IP → domain). SRV: Service discovery.

Question 3

What is TTL in DNS?

Accepted Answer

TTL (Time To Live) is how long resolvers cache a DNS record before querying again, in seconds. Lower TTL means faster propagation of changes but more DNS queries. Common TTLs: 300 (5 min, before migrations), 3600 (1 hour, typical), 86400 (1 day, stable records).

Question 4

How long does DNS propagation take?

Accepted Answer

DNS changes propagate based on the old record's TTL. If TTL was 3600 seconds, it can take up to 1 hour for all resolvers to update. To speed up propagation before planned changes, lower the TTL to 300 (5 minutes) 24 hours in advance. Global propagation usually completes within 24-48 hours.

Question 5

What is the difference between A and CNAME records?

Accepted Answer

An A record points directly to an IP address. A CNAME (Canonical Name) is an alias that points to another domain name, which then resolves to an IP. CNAMEs are useful for pointing multiple names to the same service. However, CNAME is not allowed at the domain apex (root) — use ALIAS or ANAME records instead.

Question 6

How do I do a DNS lookup online?

Accepted Answer

Enter a domain name above and select the record type (A, AAAA, MX, TXT, CNAME, NS, etc.). The tool queries public DNS resolvers and displays the current DNS records. Useful for verifying DNS propagation after changes, troubleshooting email delivery (MX records), and checking SPF/DKIM records (TXT). DNS changes typically propagate globally within 24-48 hours.

Question 7

How do I check DNS propagation?

Accepted Answer

DNS propagation is the time it takes for DNS changes to spread across all resolvers worldwide. After updating records, use the lookup above to query from multiple locations. New TTL values take effect after the old TTL expires. To speed propagation, lower the TTL before making changes. Full global propagation typically takes 24-48 hours for TTL values of 86400 seconds.

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