Offline DNS Record Analyzer
Paste DNS records in zone-file or dig answer format and press Analyze. The analyzer parses them in a Web Worker on your device and lists errors, warnings and notes, such as two SPF records at one name, a CNAME next to other records, or a DMARC record without a policy. Nothing is sent over the network.
This tool runs in an isolated frame on tools.freetoolspro.com. Your files and inputs stay on your device, and advertising on this page cannot read them.
What it checks
Owner-name and IP syntax for A/AAAA; duplicate records; CNAME conflicts and CNAME at the apex; MX preference and host-name targets, MX pointing at a CNAME; CAA flags and tags; SOA fields; TTLs under 60 s or over one week and mixed TTLs in a record set; TXT strings over 255 bytes; SPF version, terms, deprecated ptr, “+all” and the 10-lookup limit (top level); DMARC version, policy, pct and report addresses; the obsolete SPF record type.
Privacy
Analysis runs in the isolated tools.freetoolspro.com frame, whose security policy blocks connections to other sites. Your pasted records are not uploaded, stored or shown to advertising scripts on this page.
Limits
It checks what you paste, not what is live in DNS. Nested SPF includes are not expanded offline, so the real lookup count may be higher. Passing these checks does not guarantee mail deliverability.
Common questions
Can I paste output from dig?
Yes. Answer lines such as “example.com. 299 IN A 192.0.2.1” are records in zone-file syntax. Comment lines starting with “;” are ignored.
Does it change my DNS?
No. It only reads the text you paste.
Methodology reviewed 2026-10-27. Processing details and test approach.