Identity
72
B
debian.org
Posture Score: 81/100
Scanned May 8, 2026 at 8:14 AM UTC
Attack Surface
79
Reputation
91
Identity Findings
No DKIM records found
No DKIM records were found for any common selector. Email may not be authenticated.
💡 Configure DKIM signing and publish the public key at <selector>._domainkey.debian.org
DMARC policy is monitoring-only (p=none)
The p=none policy only monitors; it does not instruct receivers to quarantine or reject unauthenticated mail.
💡 Upgrade to p=quarantine or p=reject after reviewing aggregate reports.
No MTA-STS record found
Without MTA-STS, mail transport encryption cannot be enforced and is vulnerable to downgrade attacks.
💡 Publish a _mta-sts TXT record and host a policy file at https://mta-sts.debian.org/.well-known/mta-sts.txt
SOA MNAME is not authoritative
The primary nameserver (MNAME) 'denis.debian.org' does not return authoritative answers.
💡 Update the MNAME field to point to an authoritative nameserver for this zone.
No TLS-RPT record found
Without TLS-RPT, you will not receive reports about TLS negotiation failures.
💡 Publish a _smtp._tls TXT record (e.g. "v=TLSRPTv1; rua=mailto:tls-reports@debian.org").
ARC support not detected
No evidence of ARC (Authenticated Received Chain) support on MX servers. Forwarded messages may lose authentication.
💡 Consider enabling ARC signing on your mail servers to preserve authentication through forwarding.
Very low TTL on A records: 282s
4 A records have a TTL of 282s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on AAAA records: 282s
4 AAAA records have a TTL of 282s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on SPF record: 272s
The SPF record has a TTL of 272s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on TXT records: 272s
2 TXT records have a TTL of 272s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on DMARC record: 272s
The DMARC record has a TTL of 272s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
NS TTL mismatch between parent and authoritative zone
The NS record TTL in the parent zone (~7172s) differs significantly from the authoritative zone (~28800s).
💡 Align NS record TTLs between the parent zone delegation and the authoritative zone.
SPF record is valid
The SPF record is properly configured with valid syntax and within lookup limits.
DKIM cryptographic configuration is compliant
No RFC 8301 compliance issues detected in DKIM key configuration.
No deprecated DMARCbis tags present
The DMARC record does not use any tags deprecated in DMARCbis (pct, rf, ri).
MX records are valid
All MX records are properly configured.
SMTP security checks passed
No open relay, VRFY/EXPN, or banner disclosure issues detected.
SMTP RFC 5321 compliance checks passed
The mail server accepts postmaster@ and abuse@ and uses a valid FQDN in EHLO.
IPv6 readiness is good
IPv6 records are present and properly configured.
STARTTLS downgrade resistance is adequate
STARTTLS is supported with modern TLS and protected by MTA-STS and/or DANE.
NS delegation is properly configured
All nameservers are responsive, consistent, and properly secured.
DNS responses are consistent across all nameservers
All authoritative nameservers return consistent answers with proper AA flags.
DKIM2 not detected
No DKIM key record with v=2 was found across common selectors. DKIM2 is an emerging standard and not yet widely deployed.
DMARC alignment: adkim=r, aspf=r
DKIM alignment is relaxed, SPF alignment is relaxed.
DMARCbis np tag absent
The DMARC record does not include the np (non-existent subdomain policy) tag. Consider adding np=reject to protect non-existent subdomains under DMARCbis.
DMARCbis psd tag absent
The DMARC record does not include the psd (public suffix domain) indicator. Consider adding psd=n to explicitly identify this as an organizational domain.
DANE/TLSA configured for mailly.debian.org
TLSA records found and TLS certificate is available for verification.
DANE/TLSA configured for muffat.debian.org
TLSA records found and TLS certificate is available for verification.
DANE/TLSA configured for mitropoulos.debian.org
TLSA records found and TLS certificate is available for verification.
No BIMI record found
BIMI is not configured. Your brand logo will not display in supporting email clients.
Open mail ports on mailly.debian.org
Detected open mail-related ports: 25
RFC 8058 one-click unsubscribe assessment
No DKIM signing detected. RFC 8058 one-click unsubscribe requires DKIM-signed List-Unsubscribe headers.
MX IP network diversity
MX IPs span 3 different /16 networks, providing good diversity.
SOA record parameters
Serial: 2026050809, Refresh: 1800s, Retry: 600s, Expire: 1814400s, Min TTL: 600s
Authorized certificate authorities
CAA records restrict certificate issuance to: letsencrypt.org;validationmethods=dns-01;accounturi=https://acme-v02.api.letsencrypt.org/acme/acct/346607
Attack Surface Findings
Weak DNSSEC RSA key: 336 bits
The DNSKEY uses an RSA key of 336 bits, below the recommended 2048 bits.
💡 Generate a new DNSKEY with at least 2048-bit RSA or migrate to ECDSA/Ed25519.
Weak DNSSEC RSA key: 336 bits
The DNSKEY uses an RSA key of 336 bits, below the recommended 2048 bits.
💡 Generate a new DNSKEY with at least 2048-bit RSA or migrate to ECDSA/Ed25519.
DNS ANY query returns 33 record(s)
The DNS server responds to ANY queries with 33 record(s), creating significant DNS amplification risk.
💡 Configure the DNS server to refuse or minimize ANY query responses per RFC 8482.
Domain enumerability: low
The domain has low enumerability. Proper NSEC3 configuration and limited CT exposure reduce the attack surface.
No internal information leakage detected
No non-routable IP addresses or internal references were found in public DNS records.
8 subdomain(s) discovered for debian.org
Subdomains were enumerated via Certificate Transparency logs, DNS wordlist brute-forcing, and DNS record analysis.
0 certificate(s) found in CT logs
Certificate Transparency logs contain 0 certificate(s) for debian.org and its subdomains. Each certificate reveals subdomain names.
NSEC3 authenticated denial of existence
The domain uses NSEC3 with 0 iteration(s) and salt '-'.
1 email SRV record(s) found
Email service SRV records expose mail server configuration for automatic client setup.
DNSSEC is enabled
DNSKEY and/or DS records are present, indicating DNSSEC is configured.
Reputation Findings
Missing domain locks: clientDeleteProhibited
Domain debian.org is missing protective locks: clientDeleteProhibited.
💡 Enable clientTransferProhibited and clientDeleteProhibited locks through your registrar to prevent unauthorized transfers or deletions.
HSTS enabled but missing preload directive on debian.org
Strict-Transport-Security: max-age=15552000
💡 Add the "preload" directive to the HSTS header and submit the domain to hstspreload.org.
security.txt present
Found security.txt at https://debian.org/.well-known/security.txt.
TLS certificate valid for 82 days
Certificate for debian.org expires on 2026-07-30.
Certificate issued by R13
The certificate for debian.org is issued by a third-party CA.
Signature algorithm: rsa-sha256
The certificate for debian.org uses an acceptable signature algorithm.
RSA key: 2048 bits
The certificate for debian.org uses an adequate RSA key of 2048 bits.
SCTs present in certificate
The certificate for debian.org contains Signed Certificate Timestamps.
No weak ciphers detected
No known weak cipher suites detected on debian.org.
Domain valid for 305 days
Domain debian.org expires on 2027-03-10.
Google Safe Browsing DNS check — no flag detected
DNS-based Safe Browsing lookup returned no results. Full verification requires the Google Safe Browsing API key.
Abuse contact lookup failed
Could not query abuse contact information.
PhishTank — API key required
PhishTank phishing database check requires an API key.
Sender Score — API key required
Sender Score reputation check requires an API key.
Cisco Talos — API key required
Cisco Talos IP reputation check requires an API key.
Could not connect to webmail.debian.org
HTTPS request to https://webmail.debian.org failed or timed out.
WHOIS registration data
Registrar: Gandi SAS | Created: 1999-03-10 | Expires: 2027-03-10 | Updated: 2026-01-14
WHOIS privacy protection enabled
Domain debian.org has WHOIS privacy/redaction enabled.
Dependency Chains
DMARC Authentication Chain (SPF)
DMARC uses SPF to verify that emails come from authorized servers
SPF Record
SPF record found and configured
→
DMARC Policy
DMARC policy: none
DMARC Authentication Chain (DKIM)
DMARC uses DKIM to verify that emails have not been tampered with
DKIM Signature
DKIM signature missing
→
DMARC Policy
DMARC policy: none
⚠️ DKIM signature is missing. DMARC relies on DKIM to verify email integrity and prevent tampering. Without DKIM, DMARC alignment will fail for cryptographic verification.
Mail Server Identity: mailly.debian.org
PTR record proves mail server legitimacy
MX: mailly.debian.org
Mail server at 82.195.75.114
→
PTR Record
Reverse DNS: mailly.debian.org
Mail Server Identity: muffat.debian.org
PTR record proves mail server legitimacy
MX: muffat.debian.org
Mail server at 209.87.16.33
→
PTR Record
Reverse DNS: muffat.debian.org
Mail Server Identity: mitropoulos.debian.org
PTR record proves mail server legitimacy
MX: mitropoulos.debian.org
Mail server at 194.177.211.212
→
PTR Record
Reverse DNS: mitropoulos.debian.org
Mail Server Reputation: mailly.debian.org
RBL check ensures server is not blacklisted
MX: mailly.debian.org
Mail server at 82.195.75.114
→
RBL Status
Not blacklisted
Mail Server Reputation: muffat.debian.org
RBL check ensures server is not blacklisted
MX: muffat.debian.org
Mail server at 209.87.16.33
→
RBL Status
Not blacklisted
Mail Server Reputation: mitropoulos.debian.org
RBL check ensures server is not blacklisted
MX: mitropoulos.debian.org
Mail server at 194.177.211.212
→
RBL Status
Not blacklisted
Enforced Encryption Chain
MTA-STS enforces TLS encryption to prevent man-in-the-middle attacks
TLS Support
Mail servers support TLS encryption
→
MTA-STS Policy
MTA-STS not configured
⚠️ MTA-STS policy is missing. Even with TLS support, you lack the enforcement layer that prevents attackers from stripping encryption (downgrade attacks).
Brand Identity Chain
BIMI displays your logo in email clients, but requires DMARC enforcement
DMARC Enforcement
DMARC not enforced (p=none or missing)
→
BIMI Record
BIMI not configured
⚠️ DMARC is not enforced. BIMI requires a DMARC policy of "quarantine" or "reject" to prove you have strong email authentication. Without enforcement, email clients will not display your logo.
TLS Monitoring Chain
TLS-RPT provides reports about TLS connection failures
TLS Support
Mail servers support TLS encryption
→
TLS-RPT Reporting
TLS-RPT not configured
⚠️ TLS-RPT is not configured. Without TLS reporting, you have no visibility into TLS connection failures that may be impacting email delivery.
Security Checks
MX Records
✓
SPF Record
✓
DKIM Record
✗
DMARC Policy
✓
BIMI Record
✗
CAA Records
✓
DNSSEC
✓
MTA-STS
✗
TLS-RPT
✗
Embed Badge
Display your domain's security grade on your website or README:
<img src="https://scan.ractermx.com/badge/debian.org.svg" alt="Email Security Grade">
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