Security Protocol Diagnostic
MTA-STS Check
Audit your Mail Transfer Agent Strict Transport Security. We verify DNS records and policy availability to ensure encrypted SMTP communication.
Diagnostic Report
example-domain.io
error
Security Alert
dns
_mta-sts TXT Record
FOUND
v=STSv1; id=20231102T010101;
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HTTPS Policy Endpoint
FAILED (404)
No policy file found at https://mta-sts.example-domain.io/.well-known/mta-sts.txt
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Policy Configuration
Undefined
Mode
Unknown
Max Age
0 Seconds
security
Quick Insight
MTA-STS protects against MITM attacks and TLS downgrade. Your domain is currently vulnerable to eavesdropping.
Remediation Steps
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Publish DNS Record
DNS _mta-sts TXT verified.
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Setup HTTPS Subdomain
Point mta-sts.domain.io to a server.
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Host Policy File
Serve valid STS policy over HTTPS.
Generate Secure Policy
Create a compliant mta-sts.txt file for your domain.
ENFORCE MODE RECOMMENDED
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OUTPUT: mta-sts.txt
version: STSv1 mode: enforce mx: mx1.example-domain.io mx: mx2.example-domain.io max_age: 604800
Upload this file to
https://mta-sts.example-domain.io/.well-known/mta-sts.txt