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DNS Zone File Inspector
Inspect supported DNS zone-file records and find structural conflicts offline.
DNS master-file text
dns-zone-file-inspector.json (complete report)
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter values using the examples, or choose a local file where requested. Follow the displayed supported input shapes and limits.
- Choose Calculate result and inspect the complete result.
- Download result to save the primary file. Where supplied, additional links save source files and the full JSON report. Reset restores examples and clears output.
Examples
DNS master-file text: $ORIGIN example.com.
$TTL 300
@ IN SOA ns.example.com. hostmaster.example.com. (1 3600 600 86400 300)
@ IN NS ns.example.com.
@ IN A 192.0.2.1
ns IN A 192.0.2.53
www IN CNAME @
Limitations
- Offline IN-class master-file inventory. Support $ORIGIN/$TTL,owner inheritance,explicit TTL/class in either order,decimal or w/d/h/m/s times,comments and balanced multiline parentheses. $TTL overrides inherited record TTL;without it use the last explicit TTL,no SOA-MINIMUM fallback. Require an origin for relative names;ASCII alnum/underscore labels with internal hyphens and optional leading wildcard only,no escaped name octets or IDNA conversion. Types:A,AAAA(including strict embedded IPv4),NS,CNAME,PTR,MX,SOA,TXT,SRV,CAA,DNSKEY,DS. Typed data canonicalizes names/numbers/IPs,retains UTF8/escaped TXT bytes and chunk boundaries,and checks bounded wire fields. DNSKEY protocol3/key1–8192bytes;DS known digest lengths1/2/4,unknown digest types remain opaque. Report duplicates,CNAME coexistence/multiple targets and RRset TTL conflicts. No includes/generation/unknown types/classes,physical newline inside quotes or macros. At most2000 records/2200 logical entries/20000 tokens/8 grouping levels,TXT chunks255 bytes/RDATA65535bytes;shared input/output limits apply. Not authoritative-zone,DNSSEC or server validation;no DNS requests.
- Text fields are limited to100,000 UTF16 units each and400,000 combined UTF8 bytes; file fields have their own displayed limits. Combined output is at most4MiB. Processing stops after30 seconds; tool-specific bounds may be tighter.
- Generated source is a downloadable result and is not executed here. Inspection does not establish remote behavior, trust or standards certification.
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