mta-sts.txt (RFC 8461 SMTP MTA-STS policy)
An SMTP MTA-STS policy in enforce mode listing three MX patterns, one of them a wildcard, with a seven-day max_age. RFC 8461 specifies CRLF line endings, so this fixture is written with them deliberately - for testing policy parsers that split on bare LF.
version: STSv1
mode: enforce
mx: mail.example.com
mx: mail2.example.com
mx: *.mailhost.example.net
max_age: 604800
Specifications
- Seed
- 70400
- Site
- example.com (fictional)
- Format
- MTA-STS policy (RFC 8461)
- Mode
- enforce
- Mx Patterns
- 3
- Max Age
- 604800
- Line Endings
- CRLF
- Location
- /.well-known/mta-sts.txt
Testing contract
Expected to pass- Scenario
- Fetch and parse the MTA-STS policy for a domain.
- Expected result
- Six key/value pairs parse from CRLF-separated lines, the three mx values accumulate into a list rather than overwriting each other, and mail.mailhost.example.net matches the wildcard pattern while mail.other.example does not.
What is a .txt file?
TXT is a plain-text file containing unformatted character data with no styling or structure beyond line breaks. Its interpretation depends on character encoding, most commonly UTF-8, and on line-ending convention. It is the most universal and portable text container.
How to use this file
Use an example TXT to test encoding detection, line-ending (LF versus CRLF) handling, and any tool that reads or streams raw text input.
How to use this file for testing
“mta-sts.txt (RFC 8461 SMTP MTA-STS policy)” is a deterministic Novus Examples fixture for Web assets, Config parsing, Editor testing. Favicons, web app manifests, service workers, robots and sitemap files, Open Graph images, and .well-known resources — for testing web tooling, crawlers, PWA installers, and asset pipelines.
Documented properties for this file: seed 70400 · CRLF · MTA-STS policy (RFC 8461). Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such — expect parsers to fail loudly rather than silently accept them.
Web-platform fixtures are standards-compliant samples against fictional example.com data. Test crawlers, PWA installers and manifest validators, favicon/icon pipelines, service-worker registration, or .well-known parsers against the documented structure.
Related files
- txtsecurity.txt (RFC 9116)An RFC 9116 security.txt with Contact, Expires, Encryption, and Policy fields — normally served at /.well-known/security.txt, for testing security.txt parsers.
- txtads.txtAn IAB ads.txt listing authorised digital sellers with account IDs and relationships (sample data) — for testing ads.txt parsers and ad-fraud tooling.
- txthumans.txtA humans.txt crediting the people and stack behind a site, in the conventional TEAM/SITE block format — for testing plain-text metadata parsers.
- txtPlain-text sitemap (one URL per line)The plain-text sitemap format the sitemaps.org protocol also accepts: one absolute URL per line, no markup, UTF-8 encoded. For testing that a crawler supports the text form as well as XML.
- txtrobots.txtA robots.txt with wildcard and per-agent rules, a crawl-delay, and a sitemap reference — for testing robots parsers and crawler policy handling.
- txtrobots.txt - block everything except one pathA robots.txt that disallows the entire site for every crawler while allowing one media path for a single image agent. For testing full-block handling and the common misconception that a Disallow removes a URL from a search index.
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