Email authentication

letsencrypt.org SPF validation

Cached SPF record analysis for this domain.

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SPF validation

Record found

Valid SPF record

Query name

letsencrypt.org

Terminal all

DNS lookup count

SPF record count

SPF record

v=spf1 include:_spf.google.com ip4:23.178.112.0/24 ip4:66.133.109.36 ip4:64.78.152.132 include:mail.zendesk.com include:_spf.intacct.com -all

Mechanisms

+include:_spf.google.com+ip4:23.178.112.0/24+ip4:66.133.109.36+ip4:64.78.152.132+include:mail.zendesk.com+include:_spf.intacct.com-all

Recommendations

pair with DMARC Analyzer and DKIM Validator before tightening mail authentication enforcement

Tool switcher

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Same target (letsencrypt.org) — open the next tool without retyping.

Email Auth CheckerSame targetRun SPF, DMARC, and DKIM checks in one auditletsencrypt.orgOpen
DMARC AnalyzerSame targetDMARC policy, alignment and reporting checksletsencrypt.orgOpen
DKIM ValidatorSame targetDKIM selector lookup and record validationletsencrypt.orgOpen
DNS CheckerSame targetAll major record types in one passletsencrypt.orgOpen
DIGSame targetOne record type, resolver-style answerletsencrypt.orgOpen
Domain IP LookupSame targetA and AAAA IP addresses for a domainletsencrypt.orgOpen
Domain Age CheckerSame targetCreation date, age, registrar and expiryletsencrypt.orgOpen
WHOISSame targetRegistrar, expiry and domain statusletsencrypt.orgOpen
HTTP Header CheckerSame targetResponse headers, redirects and cachingletsencrypt.orgOpen
HTTP/2 TesterSame targetHTTP/2 support, ALPN and TLS negotiationletsencrypt.orgOpen
SSL Certificate CheckerSame targetCertificate chain, SAN and TLS versionletsencrypt.orgOpen
CAA Record CheckerSame targetCheck CAA DNS records, authorized CAs, issuewild and iodefletsencrypt.orgOpen
Blacklist CheckerSame targetDNSBL reputation for IP and domainletsencrypt.orgOpen
Punycode ConverterSame targetUnicode ↔ Punycode for IDN domainsletsencrypt.orgOpen
URL SplitterSame targetBreak a URL into parts and query paramshttps://letsencrypt.org/Open
Base64 CodecEncode and decode Base64 textOpen
Password GeneratorStrong random passwords for ops workOpen
Password Strength CheckerEntropy, crack time and password suggestionsOpen
Passphrase GeneratorMemorable random word phrases for safer sharing testsOpen
BIN CheckerCard brand, bank and country from BIN/IINOpen
IP CalculatorSubnet math for IPv4 and IPv6 CIDROpen
Browser Update CheckerBrowser version, update status and Client HintsOpen

Full tool catalog →

Guides

Practical guides for common SPF Validator tasks — DNS records, troubleshooting steps, and links to our free tools.

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SPF TXT record basics at the domain apex. SPF authorizes mail senders through a single v=spf1 TXT record published at the domain apex, not at _dmarc or DKIM selectors. DN01 returns parsed mechanisms, lookup estimates, warnings, and a shareable result URL for the same domain after DNS changes.
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Terminal all qualifiers: pass, fail, softfail, neutral. SPF authorizes mail senders through a single v=spf1 TXT record published at the domain apex, not at _dmarc or DKIM selectors. DN01 returns parsed mechanisms, lookup estimates, warnings, and a shareable result URL for the same domain after DNS changes.
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SPF DNS lookup limit and flattening. SPF authorizes mail senders through a single v=spf1 TXT record published at the domain apex, not at _dmarc or DKIM selectors. DN01 returns parsed mechanisms, lookup estimates, warnings, and a shareable result URL for the same domain after DNS changes.
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SPF alignment with DMARC enforcement. SPF authorizes mail senders through a single v=spf1 TXT record published at the domain apex, not at _dmarc or DKIM selectors. DN01 returns parsed mechanisms, lookup estimates, warnings, and a shareable result URL for the same domain after DNS changes.
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Shareable SPF validator result pages. SPF authorizes mail senders through a single v=spf1 TXT record published at the domain apex, not at _dmarc or DKIM selectors. DN01 returns parsed mechanisms, lookup estimates, warnings, and a shareable result URL for the same domain after DNS changes.
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SPF validation

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Related articles

SPF TXT record basics at the domain apex

Include mechanisms and third-party senders

Terminal all qualifiers: pass, fail, softfail, neutral

SPF DNS lookup limit and flattening

SPF alignment with DMARC enforcement

Shareable SPF validator result pages