Identity
39
F
irs.gov
Posture Score: 55/100
Scanned May 23, 2026 at 11:21 PM UTC
Attack Surface
64
Reputation
62
Identity Findings
No MX records found
The domain has no MX records and cannot receive email.
💡 Publish MX records pointing to your mail server(s).
Overly broad CIDR range: 2610:30::/32
The /32 CIDR block authorizes a very large IP range to send email as this domain.
💡 Narrow the IP range to only the specific servers that send email.
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.irs.gov
External report destination not authorized: ofdp.irs.gov
The rua= URI sends reports to ofdp.irs.gov, but no authorization record exists at irs.gov._report._dmarc.ofdp.irs.gov. Reports will be silently dropped by compliant receivers.
💡 Ask the owner of ofdp.irs.gov to publish a TXT record at irs.gov._report._dmarc.ofdp.irs.gov containing 'v=DMARC1'.
External report destination not authorized: ofdp.irs.gov
The ruf= URI sends reports to ofdp.irs.gov, but no authorization record exists at irs.gov._report._dmarc.ofdp.irs.gov. Reports will be silently dropped by compliant receivers.
💡 Ask the owner of ofdp.irs.gov to publish a TXT record at irs.gov._report._dmarc.ofdp.irs.gov containing 'v=DMARC1'.
External DMARC report destination not authorized: ofdp.irs.gov
The rua= URI points to ofdp.irs.gov but no authorization record exists at irs.gov._report._dmarc.ofdp.irs.gov.
💡 Ask the owner of ofdp.irs.gov to publish a TXT record at irs.gov._report._dmarc.ofdp.irs.gov with 'v=DMARC1'.
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.irs.gov/.well-known/mta-sts.txt
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@irs.gov").
ARC check skipped — no MX records
Cannot assess ARC support without MX records.
SPF record length OK (47 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.
Subdomains protected (sp=reject)
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).
Meets bulk sender authentication requirements
Domain has SPF, DKIM, and DMARC — meeting Google/Yahoo 2024 bulk sender requirements for email authentication.
IPv6 readiness is good
IPv6 records are present and properly configured.
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=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.
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 check skipped — no MX records
Cannot check DANE/TLSA without MX records.
No BIMI record found
BIMI is not configured. Your brand logo will not display in supporting email clients.
Open relay check skipped — no MX records
Cannot test for open relay without MX records.
SMTP compliance check skipped — no MX records
Cannot test SMTP compliance without MX records.
Port exposure check skipped — no MX records
Cannot scan ports without MX records.
STARTTLS downgrade check skipped — no MX records
Cannot test STARTTLS without MX records.
RFC 8058 one-click unsubscribe assessment
No DKIM signing detected. RFC 8058 one-click unsubscribe requires DKIM-signed List-Unsubscribe headers.
FCrDNS check skipped — no MX records
Cannot perform FCrDNS without MX records.
SOA record parameters
Serial: 2010093193, Refresh: 3600s, Retry: 1800s, Expire: 2419200s, Min TTL: 900s
Attack Surface Findings
NSEC records enable zone walking
The domain uses NSEC records for DNSSEC authenticated denial of existence. NSEC records can be walked to enumerate all names in the zone, effectively disclosing the entire zone contents.
💡 Switch from NSEC to NSEC3 with opt-out to prevent zone enumeration. Use NSEC3 with a random salt and sufficient iterations.
Domain enumerability: high
The domain is highly enumerable. Zone transfers, NSEC zone walking, or a combination of factors make it easy to discover all DNS records.
💡 Restrict zone transfers, use NSEC3 instead of NSEC, consider wildcard certificates to reduce CT log exposure, and implement rate limiting on DNS queries.
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.
NSEC used instead of NSEC3 (zone enumeration possible)
The domain uses NSEC records for authenticated denial of existence. NSEC allows zone walking.
💡 Migrate from NSEC to NSEC3 to prevent zone enumeration.
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 email autodiscovery endpoints detected
No Microsoft Autodiscover, Mozilla Autoconfig, or email SRV records were found.
5 subdomain(s) discovered for irs.gov
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 irs.gov and its subdomains. Each certificate reveals subdomain names.
DNSSEC is enabled
DNSKEY and/or DS records are present, indicating DNSSEC is configured.
Reputation Findings
Listed on dnsbl.spfbl.net
152.216.7.167 (emge.irs.gov) is listed on blacklist dnsbl.spfbl.net (response: 127.0.0.4).
💡 Visit the dnsbl.spfbl.net website to request delisting. Investigate the root cause (compromised account, open relay, spam) before requesting removal.
Could not retrieve TLS certificate
Failed to connect to irs.gov:443 or retrieve the peer certificate.
💡 Ensure the domain has a valid TLS certificate installed and port 443 is accessible.
Missing domain locks: clientDeleteProhibited
Domain irs.gov is missing protective locks: clientDeleteProhibited.
💡 Enable clientTransferProhibited and clientDeleteProhibited locks through your registrar to prevent unauthorized transfers or deletions.
Domain valid for 72 days
Domain irs.gov expires on 2026-08-04.
No disposable email provider MX records
MX records for irs.gov do not match known disposable email provider patterns.
Domain is 10460 days old
Domain irs.gov was registered 1997-10-02.
No wildcard MX records
No wildcard MX records detected for irs.gov.
TLD has good reputation
The .gov 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 (emgc.irs.gov) uses TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 including Forward Secrecy.
SMTP banner matches infrastructure identity
The SMTP banner (emg4.irs.gov) aligns with the MX hostname (emgc.irs.gov).
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.
Could not connect to irs.gov
HTTPS request to https://irs.gov failed or timed out.
Could not connect to webmail.irs.gov
HTTPS request to https://webmail.irs.gov failed or timed out.
WHOIS registration data
Registrar: get.gov | Created: 1997-10-02 | Expires: 2026-08-04 | Updated: 2025-08-09
WHOIS privacy protection enabled
Domain irs.gov has WHOIS privacy/redaction enabled.
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: irs.com (has MX!), irs.net (has MX!), irs.org (has MX!), its.gov, irs.io
5 registered lookalike domain(s) that could be used for phishing against your brand. 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: emgc.irs.gov
PTR record proves mail server legitimacy
MX: emgc.irs.gov
Mail server at 152.216.11.139
→
PTR Record
Reverse DNS: emgc.irs.gov
Mail Server Identity: emge.irs.gov
PTR record proves mail server legitimacy
MX: emge.irs.gov
Mail server at 152.216.7.167
→
PTR Record
Reverse DNS: emge.irs.gov
Mail Server Identity: emgw.irs.gov
PTR record proves mail server legitimacy
MX: emgw.irs.gov
Mail server at 152.216.13.169
→
PTR Record
Reverse DNS: emgw.irs.gov
Mail Server Reputation: emgc.irs.gov
RBL check ensures server is not blacklisted
MX: emgc.irs.gov
Mail server at 152.216.11.139
→
RBL Status
Not blacklisted
Mail Server Reputation: emge.irs.gov
RBL check ensures server is not blacklisted
MX: emge.irs.gov
Mail server at 152.216.7.167
→
RBL Status
Not blacklisted
Mail Server Reputation: emgw.irs.gov
RBL check ensures server is not blacklisted
MX: emgw.irs.gov
Mail server at 152.216.13.169
→
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 policy: reject
→
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-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/irs.gov.svg" alt="Email Security Grade">
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