Identity
24
C
startmail.com
Posture Score: 71/100
Scanned May 10, 2026 at 5:46 AM UTC
Score History
Attack Surface
98
Reputation
91
Identity Findings
Open recursion on nameserver: dns34.cloudns.net
The nameserver dns34.cloudns.net allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.
💡 Disable recursion on dns34.cloudns.net or restrict it to trusted networks only.
Open recursion on nameserver: dns31.cloudns.net
The nameserver dns31.cloudns.net allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.
💡 Disable recursion on dns31.cloudns.net or restrict it to trusted networks only.
Open recursion on nameserver: dns32.cloudns.net
The nameserver dns32.cloudns.net allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.
💡 Disable recursion on dns32.cloudns.net or restrict it to trusted networks only.
Open recursion on nameserver: dns33.cloudns.net
The nameserver dns33.cloudns.net allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.
💡 Disable recursion on dns33.cloudns.net or restrict it to trusted networks only.
TLS certificate hostname mismatch on mx4.startmail.com
Certificate subject 'mx.startmail.com' does not match hostname 'mx4.startmail.com'. SANs: mx.startmail.com, mx1.startmail.com, mx2.startmail.com, mx3.startmail.com, mx6.startmail.com
💡 Obtain a TLS certificate that matches the mail server hostname.
No DMARC aggregate report URI (rua=)
Without rua=, you will not receive aggregate reports about authentication results.
💡 Add rua=mailto:dmarc-reports@startmail.com to your DMARC record.
Very low TTL on MX records: 276s
4 MX records have a TTL of 276s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on TXT records: 276s
2 TXT records have a TTL of 276s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on SPF record: 276s
The SPF record has a TTL of 276s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on DMARC record: 277s
The DMARC record has a TTL of 277s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
SPF record is valid
The SPF record is properly configured with valid syntax and within lookup limits.
SPF record length OK (62 bytes)
SPF record is within safe DNS packet size limits.
DKIM records are valid
DKIM records found and validated for selectors: s1, s2
DKIM cryptographic configuration is compliant
No RFC 8301 compliance issues detected in DKIM key configuration.
DKIM key strength indicates modern key management
All DKIM keys use RSA-2048+ or Ed25519, consistent with current best practices.
No external DMARC report destinations
All DMARC report URIs point to the same domain — no external authorization needed.
Subdomains protected (sp=quarantine)
DMARC subdomain policy enforces quarantine or reject on unauthenticated subdomain mail.
MX records are valid
All MX records are properly configured.
4 MX records with 4 unique IPs
Multiple MX records provide mail delivery redundancy.
MTA-STS and TLS-RPT are properly configured
MTA-STS policy is enforced and TLS reporting is configured.
TLS-RPT report destinations are reachable
All TLS-RPT rua= URIs point to resolvable domains.
ARC support likely available
MX server software appears to support ARC headers for authentication preservation.
Meets bulk sender authentication requirements
Domain has SPF, DKIM, and DMARC — meeting Google/Yahoo 2024 bulk sender requirements for email authentication.
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.
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.
Deprecated DMARCbis tags found: pct
The DMARC record contains tags deprecated in DMARCbis: pct. Consider removing these for forward compatibility.
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.
REQUIRETLS not advertised
The primary MX does not advertise REQUIRETLS (RFC 8689). This is an emerging standard — MTA-STS and DANE provide adequate TLS enforcement for most deployments.
DANE/TLSA configured for mx1.startmail.com
TLSA records found and TLS certificate is available for verification.
DANE/TLSA configured for mx2.startmail.com
TLSA records found and TLS certificate is available for verification.
DANE/TLSA configured for mx3.startmail.com
TLSA records found and TLS certificate is available for verification.
DANE/TLSA configured for mx4.startmail.com
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 mx1.startmail.com
Detected open mail-related ports: 25
RFC 8058 one-click unsubscribe assessment
DKIM signing is configured. RFC 8058 compliance depends on List-Unsubscribe and List-Unsubscribe-Post headers being included in outbound messages and DKIM signatures.
MX IP network diversity
MX IPs span 2 different /16 networks, providing good diversity.
SOA record parameters
Serial: 2026042801, Refresh: 1200s, Retry: 180s, Expire: 1209600s, Min TTL: 300s
Authorized certificate authorities
CAA records restrict certificate issuance to: letsencrypt.org
Attack Surface Findings
Domain enumerability: low
The domain has low enumerability. Proper NSEC3 configuration and limited CT exposure reduce the attack surface.
Mozilla Autoconfig endpoint detected
The Autoconfig endpoint at autoconfig.startmail.com is publicly accessible and exposes mail server configuration details.
💡 Review the autoconfig XML to ensure it does not expose internal server names or sensitive configuration.
All MX records resolve correctly
No dangling MX records detected — all MX hostnames resolve to valid IP addresses.
Explicit MX records present
The domain has explicit MX records — no implicit A-record fallback delivery.
No internal information leakage detected
No non-routable IP addresses or internal references were found in public DNS records.
No excessive DNS information exposure detected
No HINFO, LOC, RP records, version disclosures, or zone walking vulnerabilities were found.
12 subdomain(s) discovered for startmail.com
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 startmail.com and its subdomains. Each certificate reveals subdomain names.
NSEC3 authenticated denial of existence
The domain uses NSEC3 with 0 iteration(s) and salt '1E47CD1309B063E5'.
2 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 startmail.com 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 startmail.com
Strict-Transport-Security: max-age=31536000
💡 Add the "preload" directive to the HSTS header and submit the domain to hstspreload.org.
security.txt present
Found security.txt at https://startmail.com/.well-known/security.txt.
TLS certificate valid for 53 days
Certificate for startmail.com expires on 2026-07-02.
Certificate issued by R13
The certificate for startmail.com is issued by a third-party CA.
Signature algorithm: rsa-sha256
The certificate for startmail.com uses an acceptable signature algorithm.
RSA key: 4096 bits
The certificate for startmail.com uses an adequate RSA key of 4096 bits.
SCTs present in certificate
The certificate for startmail.com contains Signed Certificate Timestamps.
No weak ciphers detected
No known weak cipher suites detected on startmail.com.
Domain valid for 1040 days
Domain startmail.com expires on 2029-03-15.
TLD has good reputation
The .com TLD is not on known abuse watchlists.
DMARC reporting destinations look legitimate
DMARC rua/ruf addresses do not point to known URL shortener services.
MX records point to stable infrastructure
No MX records point to known dynamic DNS service domains.
Strong TLS configuration on primary MX
Primary MX (mx1.startmail.com) uses TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 including Forward Secrecy.
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.startmail.com
HTTPS request to https://webmail.startmail.com failed or timed out.
WHOIS registration data
Registrar: Hosting Concepts B.V. d/b/a Registrar.eu | Created: 2000-03-15 | Expires: 2029-03-15 | Updated: 2025-07-25
WHOIS privacy protection enabled
Domain startmail.com has WHOIS privacy/redaction enabled.
Typosquat detected: sartmail.com (has MX!), starmail.com (has MX!), startmil.com (has MX!), stratmail.com (has MX!), tartmail.com
9 registered lookalike domain(s) that could be used for phishing against your brand. Showing top 5 of 9. Domains with MX records can send and receive email, making them high-risk phishing vectors.
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: quarantine
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: quarantine
⚠️ 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: mx1.startmail.com
PTR record proves mail server legitimacy
MX: mx1.startmail.com
Mail server at 145.131.90.133
→
PTR Record
Reverse DNS: mx1.startmail.com
Mail Server Identity: mx2.startmail.com
PTR record proves mail server legitimacy
MX: mx2.startmail.com
Mail server at 145.131.90.149
→
PTR Record
Reverse DNS: mx2.startmail.com
Mail Server Identity: mx3.startmail.com
PTR record proves mail server legitimacy
MX: mx3.startmail.com
Mail server at 89.146.36.66
→
PTR Record
Reverse DNS: mx3.startmail.com
Mail Server Identity: mx4.startmail.com
PTR record proves mail server legitimacy
MX: mx4.startmail.com
Mail server at 89.146.36.82
→
PTR Record
Reverse DNS: mx4.startmail.com
Mail Server Reputation: mx1.startmail.com
RBL check ensures server is not blacklisted
MX: mx1.startmail.com
Mail server at 145.131.90.133
→
RBL Status
Not blacklisted
Mail Server Reputation: mx2.startmail.com
RBL check ensures server is not blacklisted
MX: mx2.startmail.com
Mail server at 145.131.90.149
→
RBL Status
Not blacklisted
Mail Server Reputation: mx3.startmail.com
RBL check ensures server is not blacklisted
MX: mx3.startmail.com
Mail server at 89.146.36.66
→
RBL Status
Not blacklisted
Mail Server Reputation: mx4.startmail.com
RBL check ensures server is not blacklisted
MX: mx4.startmail.com
Mail server at 89.146.36.82
→
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
Mode: enforce
Brand Identity Chain
BIMI displays your logo in email clients, but requires DMARC enforcement
DMARC Enforcement
DMARC policy: quarantine
→
BIMI Record
BIMI not configured
⚠️ BIMI record is missing. Even with DMARC enforcement, you need to configure BIMI to display your brand logo in supported email clients.
TLS Monitoring Chain
TLS-RPT provides reports about TLS connection failures
TLS Support
Mail servers support TLS encryption
→
TLS-RPT Reporting
TLS failure reporting configured
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/startmail.com.svg" alt="Email Security Grade">
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