Identity
84
A
protonmail.com
Posture Score: 90/100
Scanned May 9, 2026 at 4:31 AM UTC
Score History
Attack Surface
86
Reputation
100
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.protonmail.com
No DMARC aggregate report URI (rua=)
Without rua=, you will not receive aggregate reports about authentication results.
💡 Add rua=mailto:dmarc-reports@protonmail.com to your DMARC record.
BIMI record missing logo URL (l= tag)
The BIMI record does not specify a logo URL.
💡 Add l=https://example.com/logo.svg to the BIMI record.
SPF record is valid
The SPF record is properly configured with valid syntax and within lookup limits.
SPF record length OK (38 bytes)
SPF record is within safe DNS packet size limits.
DKIM cryptographic configuration is compliant
No RFC 8301 compliance issues detected in DKIM key configuration.
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.
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.
2 MX records with 2 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.
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.
DNS TTL values follow best practices
All critical DNS record TTLs are within recommended ranges.
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=s, aspf=s
DKIM alignment is strict, SPF alignment is strict.
DMARC failure reporting: fo=1
Failure reports generated when any authentication mechanism fails.
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.
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 mail.protonmail.ch
TLSA records found and TLS certificate is available for verification.
DANE/TLSA configured for mailsec.protonmail.ch
TLSA records found and TLS certificate is available for verification.
No VMC authority URL in BIMI record
The BIMI record does not specify a VMC (a= tag). Gmail and Apple Mail require a VMC to display brand logos.
Open mail ports on mail.protonmail.ch
Detected open mail-related ports: 25
Domain is IPv4-only
No AAAA records found for the domain, MX servers, or nameservers. The domain operates on IPv4 only.
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: 2502172263, Refresh: 1200s, Retry: 144s, Expire: 1814400s, Min TTL: 7200s
Authorized certificate authorities
CAA records restrict certificate issuance to: digicert.com, letsencrypt.org, sectigo.com
Attack Surface Findings
Non-responsive IP for ns1.protonmail.com: 185.70.42.150
The subdomain ns1.protonmail.com resolves to 185.70.42.150 which is not responding on ports 80 or 443. This may indicate a decommissioned server.
💡 Verify the server at 185.70.42.150 is operational or remove the DNS record for ns1.protonmail.com.
Non-responsive IP for ns2.protonmail.com: 176.119.200.150
The subdomain ns2.protonmail.com resolves to 176.119.200.150 which is not responding on ports 80 or 443. This may indicate a decommissioned server.
💡 Verify the server at 176.119.200.150 is operational or remove the DNS record for ns2.protonmail.com.
DNS ANY query returns 44 record(s)
The DNS server responds to ANY queries with 44 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.
Mozilla Autoconfig endpoint detected
The Autoconfig endpoint at autoconfig.protonmail.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.
19 subdomain(s) discovered for protonmail.com
Subdomains were enumerated via Certificate Transparency logs, DNS wordlist brute-forcing, and DNS record analysis.
392 certificate(s) found in CT logs
Certificate Transparency logs contain 392 certificate(s) for protonmail.com and its subdomains. Each certificate reveals subdomain names.
NSEC3 authenticated denial of existence
The domain uses NSEC3 with 0 iteration(s) and salt '-'.
DNSSEC is enabled
DNSKEY and/or DS records are present, indicating DNSSEC is configured.
Reputation Findings
HSTS enabled with preload on protonmail.com
Strict-Transport-Security: max-age=31536000; includeSubDomains; preload
security.txt present
Found security.txt at https://protonmail.com/.well-known/security.txt.
TLS certificate valid for 33 days
Certificate for protonmail.com expires on 2026-06-11.
Certificate issued by R12
The certificate for protonmail.com is issued by a third-party CA.
Signature algorithm: rsa-sha256
The certificate for protonmail.com uses an acceptable signature algorithm.
RSA key: 4096 bits
The certificate for protonmail.com uses an adequate RSA key of 4096 bits.
SCTs present in certificate
The certificate for protonmail.com contains Signed Certificate Timestamps.
No weak ciphers detected
No known weak cipher suites detected on protonmail.com.
Domain valid for 104 days
Domain protonmail.com expires on 2026-08-21.
Domain transfer and delete locks enabled
Domain protonmail.com has clientTransferProhibited and clientDeleteProhibited locks.
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 (mail.protonmail.ch) 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.protonmail.com
HTTPS request to https://webmail.protonmail.com failed or timed out.
WHOIS registration data
Registrar: MarkMonitor Inc. | Created: 2010-08-21 | Expires: 2026-08-21 | Updated: 2024-07-20
WHOIS privacy protection not detected
Domain protonmail.com does not appear to have WHOIS privacy protection. Registrant details may be publicly visible.
Typosquat detected: rotonmail.com (has MX!), potonmail.com (has MX!), prtonmail.com (has MX!), proonmail.com (has MX!), protomail.com (has MX!)
29 registered lookalike domain(s) that could be used for phishing against your brand. Showing top 5 of 29. 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: mail.protonmail.ch
PTR record proves mail server legitimacy
MX: mail.protonmail.ch
Mail server at 185.205.70.128
→
PTR Record
Reverse DNS: mail.protonmail.ch
Mail Server Identity: mailsec.protonmail.ch
PTR record proves mail server legitimacy
MX: mailsec.protonmail.ch
Mail server at 185.205.70.129
→
PTR Record
Reverse DNS: mailsec.protonmail.ch
Mail Server Reputation: mail.protonmail.ch
RBL check ensures server is not blacklisted
MX: mail.protonmail.ch
Mail server at 185.205.70.128
→
RBL Status
Not blacklisted
Mail Server Reputation: mailsec.protonmail.ch
RBL check ensures server is not blacklisted
MX: mailsec.protonmail.ch
Mail server at 185.205.70.129
→
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
Brand logo configured
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/protonmail.com.svg" alt="Email Security Grade">
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