DNS Lookup Tool
A DNS lookup tool queries the Domain Name System to retrieve resource records for a domain name — such as A, MX, NS, and TXT — mapping human-readable hostnames to IPs, mail servers, and configuration data.
Enter a domain name, select a record type (A, MX, NS, TXT, etc.), and click Lookup. ScanSuite queries authoritative nameservers and returns TTL, priority, and record values you can copy for troubleshooting or verification.
Introduction to Online DNS Lookup
DNS lookup is the process of querying the Domain Name System to find which IP addresses, mail servers, and configuration records are associated with a domain name. Every website visit, email delivery, and API call depends on DNS resolving correctly.
ScanSuite's free DNS lookup tool lets you check DNS records for any public domain directly from your browser. Select a record type, enter a hostname, and get structured results with TTL values and copy-ready output — no account required.
What Is a DNS Lookup Tool?
A DNS lookup tool performs a DNS query against recursive or authoritative nameservers and returns the matching resource records. Unlike a simple ping, a lookup reveals the full chain of DNS data: which IP hosts the site (A/AAAA), which servers handle email (MX), which nameservers are authoritative (NS), and which text policies apply (TXT for SPF, DKIM, DMARC).
The Domain Name System is defined in RFC 1035 and operates hierarchically. Your query travels from stub resolver to recursive resolver to authoritative nameserver. Our tool surfaces the final answer set so you can verify configuration without using a command-line nslookup or dig client.
Why Use an Online DNS Lookup?
Online DNS lookup tools remove the need to install dig, nslookup, or host utilities — useful on locked-down corporate laptops, mobile devices, or during incident response when speed matters.
Checking DNS records before go-live prevents outages: verify MX points to the correct mail provider, confirm A records match your CDN, and ensure TXT records publish valid SPF and DMARC policies. DNS misconfiguration remains one of the top causes of email deliverability failures and website downtime.
Who Uses DNS Lookup Tools?
System administrators use DNS lookup to validate zone files after changes. DevOps engineers verify ingress and load-balancer records during deployments. Security engineers inspect TXT records for SPF/DMARC and hunt dangling CNAMEs that enable subdomain takeover.
Email administrators troubleshoot MX priority and SPF alignment. Developers debug API endpoints and certificate validation chains. Students and certification candidates practice reading real-world DNS responses alongside tools like MXToolbox and DNSChecker.
How DNS Lookup Works
When you submit a domain and record type, ScanSuite sends a DNS query to resolve the requested resource record. The resolver walks the DNS hierarchy: root → TLD nameservers → authoritative nameserver for the zone → final answer.
Results include the record type, value (IP, hostname, or text), TTL (time-to-live in seconds), and for MX records, priority. Lower MX priority numbers indicate preferred mail servers per RFC 5321 conventions.
Example: A record lookup for google.com
An A record lookup for google.com returns one or more IPv4 addresses (e.g., 142.250.x.x). Multiple A records indicate load distribution across Google's anycast network.
Example: MX lookup for github.com
An MX lookup returns mail exchange hosts with priority values. Lower priority numbers are tried first. This confirms which provider handles inbound email for the domain.
DNS Record Types Compared
| Record | Purpose | Example Value | |
|---|---|---|---|
| A | IPv4 address | 192.0.2.1 | |
| AAAA | IPv6 address | 2001:db8::1 | |
| MX | Mail server | 10 mail.example.com | |
| CNAME | Alias | target.example.com | |
| NS | Nameserver | ns1.example.com | |
| TXT | Text / SPF / DKIM | v=spf1 include:_spf.google.com ~all | |
| SOA | Zone authority | Primary NS + admin contact |
Browser vs Command-Line DNS Tools
| Feature | ScanSuite DNS Lookup | dig / nslookup | |
|---|---|---|---|
| Installation | None — browser only | Requires CLI tools | |
| Record types | A, AAAA, MX, CNAME, NS, TXT, SOA | All types via flags | |
| Copy results | One-click copy | Manual copy from terminal | |
| Signup | Not required | Not required |
DNS Lookup Troubleshooting
If no records are returned, verify the domain is registered, nameservers are configured at the registrar, and the record type exists in the zone file. NXDOMAIN indicates the name does not exist; NOERROR with empty answer means the type is not published.
Stale results may reflect DNS caching. Note the TTL and wait for expiration, or query from a resolver with a cleared cache. For split-horizon DNS, public lookups show only the external view of the zone.
Related tools
- packet-analyzer —
- Port Scanner — Free online Nmap port scan
- Subnet Calculator — Calculate CIDR blocks
- Subdomain Finder — Discover subdomains and hostnames for a domain
- Port Scanner — Scan open ports on resolved IP addresses
- What Is My IP — Check your public IP address
- Subnet Calculator — Calculate CIDR ranges and network masks
- SPF/DKIM Checker — Validate email authentication records
- SSL Checker — Inspect TLS certificates for domains
- Packet Analyzer — Analyze DNS traffic in PCAP files
- All Free Tools — Browse the complete ScanSuite tool catalog
- Network Scanning — Enterprise network vulnerability scanning
Frequently Asked Questions
How do I run nslookup online?
Enter a domain, choose a record type (A, AAAA, MX, TXT, NS, CNAME or SOA) and run the lookup. You get the same answers `nslookup` or `dig` would give, without a terminal.
How do I look up DNS TXT records?
Choose TXT and enter the domain. TXT records hold SPF policies, domain verification tokens and DKIM/DMARC data (for example `_dmarc.example.com`). To check email authentication, use the SPF/DKIM checker.
What do A, AAAA, MX, CNAME and NS records mean?
A maps a name to an IPv4 address and AAAA to an IPv6 address. MX lists the mail servers. CNAME points one name at another. NS names the domain's authoritative nameservers.
Why don't my DNS changes show up yet?
Resolvers cache records until their TTL runs out, so changes can take minutes to hours to appear everywhere. Check the TTL in the results.
How do I look up MX, NS, and TXT records?
Enter the domain and choose the record type, or query the common set. A records map the name to IPv4, MX records name the mail servers, NS records name the authoritative servers, and TXT records hold SPF and verification strings.
What is a DNS lookup?
A DNS lookup is a query to the Domain Name System that retrieves resource records for a domain name. The DNS translates human-readable hostnames like example.com into machine-readable data such as IP addresses (A/AAAA records), mail servers (MX), nameservers (NS), and text policies (TXT). Every web request begins with DNS resolution. A lookup tool lets you inspect that data directly, which is essential for troubleshooting connectivity, email, and security configuration issues.
How does the ScanSuite DNS lookup tool work?
Enter a domain name and select a record type. ScanSuite sends a DNS query to resolve the requested record against public DNS infrastructure. The resolver follows the DNS hierarchy from root nameservers through the TLD to the domain's authoritative nameserver. Results display the record type, value, TTL, and MX priority where applicable. The entire process runs in your browser without installing dig or nslookup.
What DNS record types can I look up?
ScanSuite supports A (IPv4), AAAA (IPv6), MX (mail exchange), CNAME (canonical name alias), NS (nameserver), TXT (text records including SPF and DKIM), and SOA (start of authority). Each record type serves a distinct purpose in domain configuration. Select the type matching your diagnostic goal \u2014 for example, MX for email routing or TXT for SPF verification.
What is the difference between A and AAAA records?
An A record maps a hostname to an IPv4 address (32-bit, e.g., 192.0.2.1). An AAAA record maps a hostname to an IPv6 address (128-bit, e.g., 2001:db8::1). Dual-stack domains publish both record types so clients can connect over IPv4 or IPv6. If a site loads over IPv4 but not IPv6, check whether AAAA records are published and reachable.
What is an MX record and how do I read priority?
An MX (Mail Exchange) record specifies which mail servers accept email for a domain. Each MX record includes a priority number and a hostname. Lower priority values are preferred \u2014 a record of "10 mail.example.com" is tried before "20 backup.example.com" per RFC 5321. Multiple MX records provide redundancy. If email fails, verify MX records point to active, reachable mail hosts.
What are TXT records used for?
TXT records store arbitrary text associated with a domain. Common uses include SPF policies (v=spf1...) that define authorized mail senders, DKIM public keys for email signing verification, DMARC policies for email authentication reporting, and domain ownership verification tokens for services like Google Workspace or Microsoft 365. TXT lookups are essential for email security audits.
Is this DNS lookup tool free?
Yes. ScanSuite's DNS lookup tool is free to use with no account required. You can query public DNS records for any domain without signup, subscription, or usage limits on the free tier. Premium ScanSuite features add network scanning, PCAP analysis, and enterprise reporting \u2014 but DNS lookup remains free.
Is DNS lookup legal?
Querying public DNS records is legal. DNS data is intentionally published to the global DNS system so clients worldwide can resolve domain names. However, using lookup results to attack systems you do not own or have permission to test may violate computer misuse laws and terms of service. Always ensure you have authorization when investigating domains outside your organization.
Does ScanSuite store my DNS lookup queries?
ScanSuite processes DNS queries to return results to your browser. On the free tier, lookup history is not associated with user profiles because no account is required. Queries are handled transiently for request processing. Review our Privacy Policy at scansuite.io/privacy-policy for complete data retention and handling details.
How do I check if DNS has propagated?
DNS propagation occurs as cached records expire based on TTL values across global resolvers. After a DNS change, query the record and note the TTL. Full propagation may take from minutes to 48 hours depending on previous TTL settings. For comprehensive propagation checks, query from multiple geographic resolvers or use dedicated propagation tools in addition to a single lookup.
What is the difference between NS and SOA records?
NS (Name Server) records delegate a domain to authoritative nameservers that hold the zone data. SOA (Start of Authority) records define the primary nameserver, administrative contact, serial number, refresh/retry/expire timers, and default TTL for the zone. SOA serial numbers increment after zone updates \u2014 useful for verifying whether a change has been published.
Can I use this instead of nslookup or dig?
For common record types and quick checks, yes. ScanSuite provides browser-based equivalents to nslookup and dig for A, AAAA, MX, CNAME, NS, TXT, and SOA queries. Command-line tools offer additional flags (trace, DNSSEC validation, custom resolvers) that power users may still prefer for advanced diagnostics.
What does TTL mean in DNS results?
TTL (Time To Live) is the number of seconds a DNS resolver should cache a record before querying again. A TTL of 3600 means resolvers cache the answer for one hour. Lower TTLs speed propagation after changes but increase query load. High TTLs improve performance but slow updates during migrations.
Why does my DNS lookup return no results?
Empty results may indicate the record type is not published in the zone, the domain is misspelled, nameservers are misconfigured at the registrar, or the domain has expired. NXDOMAIN means the name does not exist. Verify NS records first to confirm delegation, then query the specific record type you expect.
How do CNAME records work?
A CNAME (Canonical Name) record creates an alias from one DNS name to another. For example, www.example.com might CNAME to example.com. CNAME records cannot coexist with other record types at the same DNS name per RFC 1034. They are commonly used for CDN endpoints, SaaS platforms, and subdomain routing.
How does DNS lookup relate to email deliverability?
Email delivery depends on correct MX, SPF (TXT), DKIM (TXT), and DMARC (TXT) records. MX routes inbound mail. SPF lists authorized sending IPs. DKIM provides cryptographic signatures. DMARC defines policy for failed authentication. A DNS lookup tool is the first step in diagnosing bounce issues, spam folder placement, and authentication failures.
Can I look up DNS records for subdomains?
Yes. Enter the full subdomain in the domain field \u2014 for example, api.example.com or mail.example.com. Subdomains may have their own A, CNAME, or TXT records independent of the apex domain. This is useful for verifying API endpoints, mail subdomains, and service-specific DNS configuration.
What authoritative sources define DNS record formats?
DNS record formats are defined by IETF RFCs. RFC 1035 specifies the base DNS protocol. RFC 3596 covers AAAA records. RFC 7208 defines SPF. RFC 6376 defines DKIM. RFC 7489 defines DMARC. IANA maintains the official list of DNS resource record types. ScanSuite returns records conforming to these public standards.
Summary
ScanSuite's free DNS lookup tool queries A, AAAA, MX, CNAME, NS, TXT, and SOA records for any public domain. Use it to troubleshoot connectivity, verify email authentication, audit zone configuration, and support security investigations — directly from your browser without CLI tools or an account.