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DNS Tool

CNAME Lookup

Lookup CNAME records and verify alias target mapping for domains and subdomains. Run fast checks, interpret results, and use related tools for validation.

Record Type

CNAME

Focused record verification for targeted DNS troubleshooting.

Best Use

Migration + incident checks

Validate live DNS answers during change windows.

Operational Context

Use this page to validate live resolver output during DNS cutovers, outage triage, and post-change verification windows.

CNAME Lookup — Start Here

Waiting for input

Enter a domain and run check

How to Use

Use CNAME Lookup in 4 Steps

Enter domain

Input the target domain in clean hostname format (no path or query string).

Run CNAME Lookup

Execute CNAME Lookup to pull live resolver output for this record scope.

Compare expected vs live

Match returned values with your intended DNS configuration at the source.

Cross-check related tools

Validate adjacent DNS layers to isolate cache vs source problems.

What is CNAME Lookup?

A CNAME (Canonical Name) record creates an alias from one hostname to another. The aliased hostname then resolves to an A or AAAA record. CNAMEs are widely used for www subdomains, CDN integration (pointing to Cloudflare, Fastly, or CloudFront hostnames), and third-party service setups.

When a resolver encounters a CNAME, it follows the chain until it reaches an A or AAAA record. This indirection is useful for CDN setups — your www CNAME points to cdn.provider.com, and the CDN controls the final IP. However, CNAME chains add resolver round-trips and long chains can slow resolution. RFC 1034 prohibits CNAME at the zone apex.

Best Use

Verifying CDN or hosting provider alias chains, debugging broken www subdomain resolution, and auditing which external services have CNAME delegations.

Common Mistake

Setting a CNAME at the zone apex (root domain like example.com). RFC 1034 prohibits CNAME at the apex because the apex must coexist with SOA and NS records, which a CNAME would suppress. Use A records or a provider-specific ALIAS/ANAME type at the root.

Validation Path

Follow the CNAME chain until you reach an A or AAAA record, then verify the final IP is correct and the intermediate targets exist.

Quick Interpretation Table

Use this reference to diagnose common outcomes when running CNAME Lookup.

Observed Result	Likely Cause	Next Step
CNAME loop detected	Two records alias each other with no terminal A record	Break the loop; one hostname must terminate at an A or AAAA record
CNAME target is NXDOMAIN	The alias points to a non-existent hostname	Update CNAME target to the correct hostname, or create the missing A record
CNAME at apex (example.com)	RFC violation — will break MX, TXT, and NS co-existence	Replace with an A record, or use your DNS provider's ALIAS/ANAME record type

CLI Examples

Run these commands directly from a terminal to verify CNAME records without relying on a browser-based tool.

dig CNAME www.example.com

Query the CNAME record for the www subdomain

nslookup -type=CNAME www.example.com

CNAME lookup using nslookup (cross-platform)

dig +trace www.example.com

Trace the full delegation and CNAME chain from root to final A record

dig A www.example.com

Resolve the full chain to see the final IP address (follows all CNAMEs)

Troubleshooting Workflow

Run this record check first for a scoped signal on the target hostname.
Validate nameserver authority and SOA context if results are unexpected.
Use propagation checks when different regions return different values.
Re-run after applying fixes and compare values against your expected configuration.

Frequently Asked Questions

What is a CNAME record?

A CNAME record aliases one hostname to another, creating a pointer from the queried name to a canonical target. Resolvers follow the chain until reaching an A or AAAA record. For example, `www.example.com CNAME example.com` means requests to www resolve the same IP as the root domain.

Can I use a CNAME for my root domain?

No. RFC 1034 prohibits CNAME records at the zone apex because the apex must coexist with SOA and NS records, and a CNAME would suppress them. Some DNS providers offer proprietary ALIAS or ANAME record types that behave like a CNAME at the root but are resolved server-side to A/AAAA records.

What is a CNAME chain and why does it matter?

A CNAME chain is a sequence of CNAME records pointing to each other before reaching a terminal A record. Each hop requires an additional DNS query, adding latency. RFC 1034 recommends short chains. Most CDNs limit themselves to one CNAME hop for performance.

How do I verify a CNAME resolves correctly?

Use `dig CNAME www.example.com` to see the immediate CNAME target, then `dig A www.example.com` to confirm the full chain resolves to the expected IP. Many CNAME issues arise from the target hostname being misconfigured or its A record missing.

Why does my DNS checker show a CNAME but my browser resolves an IP?

Browsers trigger a full resolution chain starting at the CNAME and ending at an A/AAAA record. Your DNS checker shows the CNAME record itself — the intermediate alias step. Both are correct — the checker shows the record, the browser shows the final resolved IP.