DNS Lookup Tool

DNS (Domain Name System) is the internet's phone book—it translates human-readable domain names like "example.com" into IP addresses that computers use to communicate. Without DNS, you'd need to memorize IP addresses for every website. DNS is critical for website accessibility, email delivery, and virtually all internet services. A misconfigured DNS can make your website unreachable or cause email to bounce.

DNS propagation is the time it takes for DNS changes to spread across all DNS servers worldwide. When you update a DNS record, the change must propagate from your authoritative nameserver to DNS resolvers globally. Propagation typically takes 1-24 hours, though it can take up to 48 hours in rare cases. The actual time depends on the TTL (Time To Live) value of your records—lower TTLs mean faster propagation but more DNS queries to your servers.

TTL (Time To Live) tells DNS resolvers how long to cache a record before checking for updates. A TTL of 3600 means resolvers cache the record for 1 hour. For stable records, use higher TTLs (3600-86400 seconds) to reduce DNS queries and improve performance. Before making changes, lower your TTL to 300-600 seconds a day in advance, make your changes, then restore the higher TTL. This minimizes downtime during DNS changes.

DNS resolvers in different geographic regions may have different cached values, especially during propagation. Checking from multiple regions helps you verify that your DNS changes have fully propagated worldwide, identify regional DNS issues, and ensure consistent resolution for global users. This is particularly important for CDN configurations, geo-targeted services, and diagnosing "works for me but not for users in X country" problems.

An A (Address) record maps a domain name to an IPv4 address. It's the most fundamental DNS record type—when someone visits your website, their browser queries the A record to find your server's IP address. You can have multiple A records for the same domain to enable load balancing or failover. For IPv6 addresses, you'd use an AAAA record instead.

MX (Mail Exchange) records specify which mail servers handle email for your domain. Each MX record has a priority value—lower numbers mean higher priority. When sending email to your domain, mail servers try the lowest priority MX first, falling back to higher priority servers if needed. For example, with priorities 10 and 20, mail goes to priority 10 first; if it's unavailable, priority 20 handles the mail.

TXT records store text data in DNS and are used for domain verification (Google, Microsoft, SSL certificates), email authentication (SPF, DKIM, DMARC), and security policies. When you add a Google Search Console verification or configure SPF for email, you're adding TXT records. They're also used for DKIM signatures, DMARC policies, and various third-party service verifications.

NS (Name Server) records specify which DNS servers are authoritative for your domain—meaning they hold the master copies of your DNS records. When you register a domain or change DNS providers, you update NS records to point to your DNS host. Most domains have 2-4 NS records for redundancy. If all your nameservers go down, your domain becomes completely unreachable.