DNS Lookup - Online Domain Records Checker (A, MX, CNAME)

A DNS (Domain Name System) lookup is the process of querying DNS servers to retrieve information about a domain name. When you type a website address into your browser, DNS translates that human-readable domain name (like google.com) into a machine-readable IP address (like 142.250.80.46). This tool performs real-time DNS queries using DNS-over-HTTPS (DoH) to fetch various record types including A, AAAA, MX, CNAME, NS, TXT, and SOA records.

An A record (Address record) maps a domain name to an IPv4 address (e.g., 93.184.216.34). It is the most fundamental DNS record type. When someone visits your website, the A record tells the browser which server IP address to connect to. A domain can have multiple A records for load balancing and redundancy. Without a valid A record, your website would be unreachable via its domain name.

An MX record (Mail Exchange record) specifies which mail servers are responsible for receiving email on behalf of a domain. Each MX record includes a priority value (lower numbers = higher priority). When sending email to an address like user@example.com, the sender's mail server looks up the MX records of example.com and attempts delivery starting with the lowest-priority server. Multiple MX records provide redundancy — if the primary mail server is unavailable, email is routed to the next available server.

A CNAME record (Canonical Name record) creates an alias from one domain name to another. For example, you might set www.example.com as a CNAME pointing to example.com. This means both addresses resolve to the same IP address without needing separate A records. CNAME records are commonly used for subdomains like www, blog, or shop. Important: You cannot create a CNAME record for the root domain (apex domain) — root domains must use A records.

NS records (Name Server records) identify which DNS servers are authoritative for a domain. These servers hold the official DNS records for the domain. When you register a domain and set nameservers (like ns1.cloudflare.com), NS records point to those servers. Typically, a domain has at least two NS records for redundancy. If NS records are misconfigured, your entire DNS setup can fail.

TXT records (Text records) store arbitrary text data associated with a domain. They serve multiple purposes including SPF (Sender Policy Framework for email authentication), DKIM (DomainKeys Identified Mail), DMARC (Domain-based Message Authentication), and domain ownership verification for services like Google Search Console, Microsoft 365, or SSL certificate providers. A single domain can have multiple TXT records.

TTL (Time To Live) is the duration (in seconds) that a DNS record is cached by resolvers and other DNS servers before they must fetch a fresh copy from the authoritative server. For example, a TTL of 3600 means the record can be cached for 1 hour. Low TTL values (60–300s) allow faster DNS changes but increase query load. High TTL values (86400s = 24h) reduce query load but slow down propagation of changes. Common TTL values range from 300s (5 min) to 86400s (24 hours).

DNS propagation is the time it takes for DNS record changes to spread across all DNS servers worldwide. When you update a DNS record, the change is not instant — cached copies on various DNS resolvers must expire (based on TTL) before fetching the new value. Propagation can take anywhere from a few minutes to 48 hours, though most changes propagate within 1–4 hours. To speed up propagation, lower the TTL value before making changes.

Common DNS issues include: NXDOMAIN errors (domain doesn't exist or DNS records are missing), SERVFAIL errors (authoritative server failure), misconfigured MX records causing email delivery failures, incorrect A records pointing to wrong IPs, CNAME conflicts (CNAME at root domain), expired domains, DNSSEC validation failures, and propagation delays. Regular DNS lookups help diagnose and troubleshoot these issues before they impact users.