DNS Lookup

What Is DNS?

The Domain Name System (DNS) is the internet's directory service. It translates human-readable domain names like google.com into machine-readable IP addresses like142.250.80.46. Without DNS, you would need to memorize numerical IP addresses for every website you visit. DNS operates as a distributed, hierarchical database spread across millions of servers worldwide, making it one of the most critical pieces of internet infrastructure.

When you type a URL into your browser, your device first checks its local DNS cache. If the answer is not cached, the query travels to your ISP's recursive resolver, which then queries the DNS hierarchy: root servers, top-level domain (TLD) servers (like those for .com or.org), and finally the authoritative nameservers for the specific domain. The entire process typically completes in under 100 milliseconds. DNS responses are cached at multiple levels to reduce load and improve speed, with each record specifying a Time To Live (TTL) that determines how long it can be cached before a fresh lookup is required.

DNS Record Types Explained

DNS supports many record types, each serving a different purpose. The most common types are:

A records map a domain name to an IPv4 address. This is the most fundamental DNS record type and is what your browser uses to find the server hosting a website.AAAA records (pronounced "quad-A") serve the same purpose but map to IPv6 addresses. As IPv6 adoption grows, AAAA records are becoming increasingly important.

MX records (Mail Exchange) specify the mail servers responsible for receiving email for a domain. They include a priority value, allowing domains to define primary and backup mail servers. NS records (Name Server) identify the authoritative DNS servers for a domain, delegating DNS resolution to those specific servers.

TXT records hold arbitrary text data and are used for a variety of purposes, including email authentication (SPF, DKIM, DMARC), domain ownership verification (for services like Google Search Console), and security policies. CNAME records (Canonical Name) create an alias from one domain name to another, commonly used to point subdomains likewww.example.com to the main domain example.com. Unlike A records, a CNAME does not resolve directly to an IP address but instead redirects the DNS lookup to follow the target domain's records.

DNS Troubleshooting Tips

DNS propagation delays are the most common source of confusion when making DNS changes. When you update a DNS record, the change does not take effect instantly across the internet. Every DNS record has a Time To Live (TTL) value that tells resolvers how long to cache the record before requesting a fresh copy. If your record had a TTL of 3600 seconds (1 hour), some resolvers will continue serving the old record for up to an hour after you make the change. To minimize propagation delays before a planned migration, lower the TTL to 300 seconds (5 minutes) at least 24 hours in advance, make your change, and then restore the original TTL once the migration is confirmed.

NXDOMAIN errors mean the domain does not exist in DNS. This can happen if the domain has expired, the nameserver delegation is broken, or the domain was never registered. Check the domain's registration status using our WHOIS lookup tool. If the domain is registered but DNS queries fail, the issue is likely with the nameserver configuration. Verify that the NS records point to the correct authoritative nameservers and that those servers are responding.

Email delivery problems are often DNS-related. If email is bouncing or landing in spam folders, check that your MX records are correctly configured and that your TXT records include valid SPF, DKIM, and DMARC policies. A missing or incorrect SPF record is one of the most common reasons for email being flagged as spam. You can verify the hostname associated with your mail server's IP using our reverse DNS lookup tool, which checks for PTR records that mail servers rely on for sender verification.