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. When you visit a website, your computer queries a DNS resolver, which traverses a hierarchy of servers (root → TLD → authoritative) to find the IP address for that domain, then caches the result for the duration of the record's TTL (Time To Live).

DNS propagation is the time it takes for DNS record changes to spread across all resolvers worldwide. After you update a record, old values remain cached until the previous TTL expires. Low TTLs (300 seconds = 5 minutes) propagate fast. Default TTLs (3600–86400 seconds) can take up to 48 hours to fully propagate. Best practice: lower your TTL to 300 before migrations, then raise it again after confirming the change.

An A record maps a domain directly to an IPv4 address (e.g. example.com → 203.0.113.1). A CNAME (Canonical Name) record creates an alias that points one domain to another domain name (e.g. www.example.com → example.com). A records are for the actual IP mapping; CNAMEs are for aliases. Important: CNAME records cannot be used at the root domain (you cannot CNAME example.com itself — only subdomains).

These are email authentication TXT records. SPF (Sender Policy Framework) lists authorised mail servers for your domain — prevents spammers from sending mail claiming to be from you. DKIM (DomainKeys Identified Mail) adds a cryptographic signature to outgoing emails, letting receivers verify they were not tampered with. DMARC tells receivers what to do (reject, quarantine, or pass) with emails failing SPF/DKIM, and sends failure reports to you. All three together dramatically improve email deliverability and protect your domain reputation.

TTL (Time To Live) is the number of seconds a DNS record is cached by resolvers and browsers before they re-query for a fresh value. A TTL of 3600 means the record is cached for 1 hour. Lower TTLs (300 seconds) mean changes propagate faster but create more DNS query load. Higher TTLs reduce load but slow propagation. For stable records, use 3600–86400. Before planned migrations or changes, temporarily reduce TTL to 300.

MX records point to mail server hostnames (not IP addresses, not provider names). For example, Google Workspace MX records point to aspmx.l.google.com, and Microsoft 365 points to your-domain.mail.protection.outlook.com. If your MX records look correct but mail is not working, also check that SPF includes your provider's mail servers, and that no conflicting or duplicate SPF records exist — only one SPF TXT record is allowed per domain.