← Back to Scanner

gmail.com

Name: gmail.com Email Security Posture Assessment
Creator: RacterMX

Posture Score: 63/100

Scanned May 9, 2026 at 12:59 AM UTC

Score History

Identity

Attack Surface

Reputation

Identity Findings

Open recursion on nameserver: ns3.google.com

The nameserver ns3.google.com allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.

💡 Disable recursion on ns3.google.com or restrict it to trusted networks only.

critical

Open recursion on nameserver: ns2.google.com

The nameserver ns2.google.com allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.

💡 Disable recursion on ns2.google.com or restrict it to trusted networks only.

critical

Open recursion on nameserver: ns4.google.com

The nameserver ns4.google.com allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.

💡 Disable recursion on ns4.google.com or restrict it to trusted networks only.

critical

Open recursion on nameserver: ns1.google.com

The nameserver ns1.google.com allows recursive queries from external sources, making it vulnerable to DNS amplification attacks.

💡 Disable recursion on ns1.google.com or restrict it to trusted networks only.

critical

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.gmail.com

high

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.

medium

SOA expire value too short

The SOA expire value is 1800s (<604,800s / 7 days). Secondary nameservers may stop serving the zone prematurely.

💡 Increase the SOA expire value to at least 604800 seconds (7 days).

medium

No CAA iodef tag configured

No iodef tag is present in the CAA records. CA policy violation reports will not be sent.

💡 Add an iodef CAA record. Example: 0 iodef "mailto:security@example.com"

low

Very low TTL on A records: 23s

4 A records have a TTL of 23s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

Very low TTL on AAAA records: 252s

4 AAAA records have a TTL of 252s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

Very low TTL on TXT records: 230s

3 TXT records have a TTL of 230s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

Very low TTL on SPF record: 230s

The SPF record has a TTL of 230s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

Very low TTL on DMARC record: 181s

The DMARC record has a TTL of 181s or less (below 300s).

💡 Increase the TTL to at least 300 seconds unless frequent changes are expected.

low

NS TTL mismatch between parent and authoritative zone

The NS record TTL in the parent zone (~7131s) differs significantly from the authoritative zone (~345600s).

💡 Align NS record TTLs between the parent zone delegation and the authoritative zone.

low

SPF record is valid

The SPF record is properly configured with valid syntax and within lookup limits.

pass

DKIM cryptographic configuration is compliant

No RFC 8301 compliance issues detected in DKIM key configuration.

pass

No deprecated DMARCbis tags present

The DMARC record does not use any tags deprecated in DMARCbis (pct, rf, ri).

pass

MX records are valid

All MX records are properly configured.

pass

MTA-STS and TLS-RPT are properly configured

MTA-STS policy is enforced and TLS reporting is configured.

pass

ARC support likely available

MX server software appears to support ARC headers for authentication preservation.

pass

SMTP security checks passed

No open relay, VRFY/EXPN, or banner disclosure issues detected.

pass

SMTP RFC 5321 compliance checks passed

The mail server accepts postmaster@ and abuse@ and uses a valid FQDN in EHLO.

pass

IPv6 readiness is good

IPv6 records are present and properly configured.

pass

STARTTLS downgrade resistance is adequate

STARTTLS is supported with modern TLS and protected by MTA-STS and/or DANE.

pass

DNS responses are consistent across all nameservers

All authoritative nameservers return consistent answers with proper AA flags.

pass

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.

informational

DMARC alignment: adkim=r, aspf=r

DKIM alignment is relaxed, SPF alignment is relaxed.

informational

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.

informational

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.

informational

No DANE/TLSA records found

DANE is not configured for any MX server. This is optional but provides strong certificate binding.

informational

No BIMI record found

BIMI is not configured. Your brand logo will not display in supporting email clients.

informational

Open mail ports on alt3.gmail-smtp-in.l.google.com

Detected open mail-related ports: 25

informational

RFC 8058 one-click unsubscribe assessment

No DKIM signing detected. RFC 8058 one-click unsubscribe requires DKIM-signed List-Unsubscribe headers.

informational

MX IP network diversity

MX IPs span 5 different /16 networks, providing good diversity.

informational

SOA record parameters

Serial: 912053511, Refresh: 900s, Retry: 900s, Expire: 1800s, Min TTL: 60s

informational

Authorized certificate authorities

CAA records restrict certificate issuance to: pki.goog

informational

Attack Surface Findings

Non-responsive IP for www.gmail.com: 2a00:1450:400b:c00::13

The subdomain www.gmail.com resolves to 2a00:1450:400b:c00::13 which is not responding on ports 80 or 443. This may indicate a decommissioned server.

💡 Verify the server at 2a00:1450:400b:c00::13 is operational or remove the DNS record for www.gmail.com.

medium

Non-responsive IP for www.gmail.com: 2a00:1450:400b:c00::12

The subdomain www.gmail.com resolves to 2a00:1450:400b:c00::12 which is not responding on ports 80 or 443. This may indicate a decommissioned server.

💡 Verify the server at 2a00:1450:400b:c00::12 is operational or remove the DNS record for www.gmail.com.

medium

Non-responsive IP for www.gmail.com: 2a00:1450:400b:c00::11

The subdomain www.gmail.com resolves to 2a00:1450:400b:c00::11 which is not responding on ports 80 or 443. This may indicate a decommissioned server.

💡 Verify the server at 2a00:1450:400b:c00::11 is operational or remove the DNS record for www.gmail.com.

medium

Non-responsive IP for www.gmail.com: 2a00:1450:400b:c00::53

The subdomain www.gmail.com resolves to 2a00:1450:400b:c00::53 which is not responding on ports 80 or 443. This may indicate a decommissioned server.

💡 Verify the server at 2a00:1450:400b:c00::53 is operational or remove the DNS record for www.gmail.com.

medium

DNS ANY query returns 23 record(s)

The DNS server responds to ANY queries with 23 record(s), creating significant DNS amplification risk.

💡 Configure the DNS server to refuse or minimize ANY query responses per RFC 8482.

medium

Domain enumerability: medium

The domain has moderate enumerability. CT logs and DNS records reveal significant information about the domain structure.

💡 Restrict zone transfers, use NSEC3 instead of NSEC, consider wildcard certificates to reduce CT log exposure, and implement rate limiting on DNS queries.

medium

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.

medium

No internal information leakage detected

No non-routable IP addresses or internal references were found in public DNS records.

pass

4 subdomain(s) discovered for gmail.com

Subdomains were enumerated via Certificate Transparency logs, DNS wordlist brute-forcing, and DNS record analysis.

informational

0 certificate(s) found in CT logs

Certificate Transparency logs contain 0 certificate(s) for gmail.com and its subdomains. Each certificate reveals subdomain names.

informational

3 email SRV record(s) found

Email service SRV records expose mail server configuration for automatic client setup.

informational

Reputation Findings

HSTS enabled but missing preload directive on gmail.com

Strict-Transport-Security: max-age=31536000; includeSubDomains

💡 Add the "preload" directive to the HSTS header and submit the domain to hstspreload.org.

low

security.txt present

Found security.txt at https://gmail.com/.well-known/security.txt.

pass

TLS certificate valid for 65 days

Certificate for gmail.com expires on 2026-07-13.

pass

Certificate issued by WR2

The certificate for gmail.com is issued by a third-party CA.

pass

Signature algorithm: rsa-sha256

The certificate for gmail.com uses an acceptable signature algorithm.

pass

ECC key: 256 bits

The certificate for gmail.com uses an adequate ECC key of 256 bits.

pass

SCTs present in certificate

The certificate for gmail.com contains Signed Certificate Timestamps.

pass

No weak ciphers detected

No known weak cipher suites detected on gmail.com.

pass

Domain valid for 95 days

Domain gmail.com expires on 2026-08-12.

pass

Domain transfer and delete locks enabled

Domain gmail.com has clientTransferProhibited and clientDeleteProhibited locks.

pass

TLD has good reputation

The .com TLD is not on known abuse watchlists.

pass

DMARC reporting destinations look legitimate

DMARC rua/ruf addresses do not point to known URL shortener services.

pass

MX records point to stable infrastructure

No MX records point to known dynamic DNS service domains.

pass

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.

informational

Abuse contact lookup failed

Could not query abuse contact information.

informational

PhishTank — API key required

PhishTank phishing database check requires an API key.

informational

Sender Score — API key required

Sender Score reputation check requires an API key.

informational

Cisco Talos — API key required

Cisco Talos IP reputation check requires an API key.

informational

Could not connect to webmail.gmail.com

HTTPS request to https://webmail.gmail.com failed or timed out.

informational

WHOIS registration data

Registrar: MarkMonitor Inc. | Created: 1995-08-13 | Expires: 2026-08-12 | Updated: 2025-07-11

informational

WHOIS privacy protection not detected

Domain gmail.com does not appear to have WHOIS privacy protection. Registrant details may be publicly visible.

informational

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: alt3.gmail-smtp-in.l.google.com

PTR record proves mail server legitimacy

MX: alt3.gmail-smtp-in.l.google.com Mail server at 192.178.213.26 → PTR Record Reverse DNS: yugrqzs-in-f26.1e100.net

Mail Server Identity: alt2.gmail-smtp-in.l.google.com

PTR record proves mail server legitimacy

MX: alt2.gmail-smtp-in.l.google.com Mail server at 142.250.102.26 → PTR Record Reverse DNS: rb-in-f26.1e100.net

Mail Server Identity: gmail-smtp-in.l.google.com

PTR record proves mail server legitimacy

MX: gmail-smtp-in.l.google.com Mail server at 172.253.116.27 → PTR Record Reverse DNS: dj-in-f27.1e100.net

Mail Server Identity: alt1.gmail-smtp-in.l.google.com

PTR record proves mail server legitimacy

MX: alt1.gmail-smtp-in.l.google.com Mail server at 173.194.76.27 → PTR Record Reverse DNS: ws-in-f27.1e100.net

Mail Server Identity: alt4.gmail-smtp-in.l.google.com

PTR record proves mail server legitimacy

MX: alt4.gmail-smtp-in.l.google.com Mail server at 142.251.127.26 → PTR Record Reverse DNS: lcfrai-in-f26.1e100.net

Mail Server Reputation: alt3.gmail-smtp-in.l.google.com