Identity
53
C
53.com
Posture Score: 79/100
Scanned May 17, 2026 at 9:52 PM UTC
Attack Surface
94
Reputation
91
Identity Findings
Weak DKIM RSA key (~1296 bits) for selector 's2'
RSA keys shorter than 2048 bits are considered weak. Current key is approximately 1296 bits.
💡 Generate a new 2048-bit (or larger) RSA key pair and update the DKIM record.
Weak DKIM RSA key (~1296 bits) for selector 'smtp'
RSA keys shorter than 2048 bits are considered weak. Current key is approximately 1296 bits.
💡 Generate a new 2048-bit (or larger) RSA key pair and update the DKIM record.
NS delegation mismatch
The registrar-delegated nameservers do not match the zone NS records.
💡 Update either the registrar NS delegation or the zone NS records to match.
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.53.com/.well-known/mta-sts.txt
BIMI logo may not be SVG Tiny PS
The logo URL returns Content-Type: text/html. BIMI requires SVG Tiny PS format.
💡 Ensure the logo is in SVG Tiny PS format.
STARTTLS without MTA-STS or DANE protection
STARTTLS alone is vulnerable to downgrade attacks. Neither MTA-STS nor DANE is configured to enforce encryption.
💡 Deploy MTA-STS and/or DANE to protect against STARTTLS stripping attacks.
No CAA records found
No CAA records are configured. Any certificate authority can issue certificates for this domain.
💡 Add CAA records to restrict certificate issuance. Example: 0 issue "letsencrypt.org"
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@53.com").
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 MX records: 281s
2 MX records have a TTL of 281s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on NS records: 282s
6 NS 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 TXT records: 281s
32 TXT records have a TTL of 281s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on SPF record: 281s
The SPF record has a TTL of 281s or less (below 300s).
💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.
Very low TTL on DMARC record: 281s
The DMARC record has a TTL of 281s 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 (53 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.
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=reject)
DMARC subdomain policy enforces quarantine or reject on unauthenticated subdomain mail.
MX records are valid
All MX records are properly configured.
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.
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.
Deprecated DMARCbis tags found: pct, ri
The DMARC record contains tags deprecated in DMARCbis: pct, ri. 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.
No DANE/TLSA records found
DANE is not configured for any MX server. This is optional but provides strong certificate binding.
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 mxb-00642301.gslb.pphosted.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
All MX IPs are in the same /16 network. Consider diversifying across networks for resilience.
SOA record parameters
Serial: 2006113143, Refresh: 10800s, Retry: 3600s, Expire: 2419200s, Min TTL: 900s
Attack Surface Findings
DNSSEC is not enabled
No DNSKEY or DS records were found. DNS responses are not cryptographically authenticated.
💡 Enable DNSSEC by generating DNSKEY records and publishing DS records at the registrar.
DNS ANY query returns 1 record(s)
The DNS server responds to ANY queries with 1 record(s). The low record count limits amplification risk, but ANY responses still aid reconnaissance.
💡 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.
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.
6 subdomain(s) discovered for 53.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 53.com and its subdomains. Each certificate reveals subdomain names.
Wildcard DNS record detected
A wildcard DNS record exists for *.53.com, resolving to 216.82.178.21. Wildcard records make subdomain brute-forcing less effective but may mask misconfigurations.
Mozilla Autoconfig endpoint detected
The Autoconfig endpoint at autoconfig.53.com is publicly accessible.
Reputation Findings
Missing Strict-Transport-Security on 53.com
The Strict-Transport-Security header is not set on https://53.com.
💡 Add the Strict-Transport-Security header with a max-age of at least 31536000 (1 year) and include the includeSubDomains directive.
Wildcard MX records detected
Domain 53.com has wildcard MX records, which can be abused for spam or phishing.
💡 Remove wildcard MX records and configure explicit MX entries only for legitimate mail-handling subdomains.
HSTS enabled but missing preload directive on webmail.53.com
Strict-Transport-Security: max-age=31536000; includeSubDomains
💡 Add the "preload" directive to the HSTS header and submit the domain to hstspreload.org.
Not listed on any DNS blacklists
Domain and MX IPs checked against 55 DNSBLs — no listings found.
security.txt present
Found security.txt at https://53.com/.well-known/security.txt.
TLS certificate valid for 208 days
Certificate for 53.com expires on 2026-12-11.
Certificate issued by Sectigo Public Server Authentication CA OV R36
The certificate for 53.com is issued by a third-party CA.
Signature algorithm: rsa-sha256
The certificate for 53.com uses an acceptable signature algorithm.
RSA key: 2048 bits
The certificate for 53.com uses an adequate RSA key of 2048 bits.
SCTs present in certificate
The certificate for 53.com contains Signed Certificate Timestamps.
No weak ciphers detected
No known weak cipher suites detected on 53.com.
No disposable email provider MX records
MX records for 53.com do not match known disposable email provider patterns.
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 (mxb-00642301.gslb.pphosted.com) uses TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 including Forward Secrecy.
SMTP banner from hosted mail provider
The MX (mxa-00642301.gslb.pphosted.com) is a hosted mail service. Banner alignment is managed by the provider and not actionable by the domain owner.
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 contacts found for MX IPs
Abuse contact information retrieved via abusix.org DNS lookup.
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.
WHOIS lookup failed
Could not retrieve WHOIS data for 53.com.
Could not determine domain age
WHOIS creation date could not be parsed for 53.com.
Bulletproof Hosting Detection — API key required
Checking IPs against known bulletproof hosting providers requires a threat intelligence API key.
Threat Intelligence Feeds — API key required
Checking domain against threat intelligence feeds requires API keys (e.g., VirusTotal, AbuseIPDB).
Typosquat detected: 53.net (has MX!), 53.org (has MX!), 533.com, 53.io, 53.co
12 registered lookalike domain(s) that could be used for phishing against your brand. Showing top 5 of 12. 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: reject
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: reject
⚠️ 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: mxb-00642301.gslb.pphosted.com
PTR record proves mail server legitimacy
MX: mxb-00642301.gslb.pphosted.com
Mail server at 205.220.165.171
→
PTR Record
Reverse DNS: mx0a-00642301.pphosted.com
Mail Server Identity: mxa-00642301.gslb.pphosted.com
PTR record proves mail server legitimacy
MX: mxa-00642301.gslb.pphosted.com
Mail server at 205.220.177.171
→
PTR Record
Reverse DNS: mx0b-00642301.pphosted.com
Mail Server Reputation: mxb-00642301.gslb.pphosted.com
RBL check ensures server is not blacklisted
MX: mxb-00642301.gslb.pphosted.com
Mail server at 205.220.165.171
→
RBL Status
Not blacklisted
Mail Server Reputation: mxa-00642301.gslb.pphosted.com
RBL check ensures server is not blacklisted
MX: mxa-00642301.gslb.pphosted.com
Mail server at 205.220.177.171
→
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:
Brand Identity Chain
BIMI displays your logo in email clients, but requires DMARC enforcement
DMARC Enforcement
DMARC policy: reject
→
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-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/53.com.svg" alt="Email Security Grade">
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