All tools
40 diagnostic tools and generators. Free to use, no account required. Type command:target in the box to jump straight to a tool.
Health Reports
Email & Authentication
mx:MX LookupList the mail servers (MX records) for a domain in priority order, resolve their IPs and check each against blacklists.
dmarc:DMARC LookupRetrieve and validate the DMARC policy of a domain: tags, syntax, alignment, reporting addresses.
spf:SPF LookupFind and validate the SPF record, expand includes, count DNS lookups (10-lookup limit) and flag syntax issues.
dkim:DKIM LookupLook up and validate a DKIM public key for a selector, including key length and flags.
email:Email HealthEmail deliverability audit: MX, SPF, DKIM, DMARC, BIMI, MTA-STS, TLS-RPT and reverse DNS in one report.
headers:Email Header AnalyzerPaste raw email headers to trace the delivery path, delays and SPF/DKIM/DMARC authentication results.
bimi:BIMI LookupValidate the BIMI record, logo URL (SVG Tiny PS) and VMC certificate reference.
mta-sts:MTA-STS CheckFetch and validate the MTA-STS DNS record and the HTTPS policy file.
tlsrpt:TLS-RPT LookupCheck the SMTP TLS Reporting record and its reporting addresses.
smtp:SMTP DiagnosticsConnect to a mail server: banner, EHLO, STARTTLS, reverse DNS, open relay and response times.
spf-raw:SPF Record ValidatorValidate an SPF record before you publish it.
DMARC Report AnalyzerUpload a DMARC aggregate (RUA) XML/GZ/ZIP report and read it as a human.
DNS Records
dns:DNS CheckAudit the authoritative name servers of a domain: consistency, SOA, glue, open recursion and response times.
a:A LookupResolve the IPv4 address (A record) of a host name.
aaaa:AAAA LookupResolve the IPv6 address (AAAA record) of a host name.
cname:CNAME LookupFind the canonical name a host name is aliased to.
ns:NS LookupList the authoritative name servers of a domain and their IP addresses.
txt:TXT LookupRetrieve all TXT records for a name — SPF, verification tokens, DKIM and more.
soa:SOA LookupShow the Start of Authority record: primary NS, serial, refresh, retry, expire and TTL values.
ptr:Reverse DNS (PTR)Look up the reverse DNS host name of an IP address and check forward confirmation.
caa:CAA LookupSee which certificate authorities are allowed to issue certificates for a domain.
srv:SRV LookupLook up service records (e.g. _sip._tls, _autodiscover._tcp).
propagation:DNS PropagationQuery 12 public resolvers around the world to see whether a DNS change has propagated.
dnssec:DNSSEC CheckCheck whether a zone is signed (DNSKEY/DS) and validates with a validating resolver.
Reputation
Web & SSL
http:HTTP CheckVerify a URL responds over HTTP/HTTPS: status, redirects, response time, security headers.
ssl:SSL Certificate CheckInspect the TLS certificate: validity, expiry, chain, SANs, issuer and protocol support.
Network & WHOIS
ping:PingICMP ping a host and measure latency and packet loss.
tcp:TCP Port CheckCheck whether a TCP port is open (host:port).
trace:TracerouteTrace the network path to a host.
whois:WHOIS / RDAPRegistration details, registrar, creation and expiry dates for a domain, or the owner of an IP block.
asn:ASN LookupFind the autonomous system, network owner and country of an IP address.
ip:IP Address InfoReverse DNS, ASN, geolocation hints and blacklist status for an IP.
Record Generators
Build a correct SPF record from your sending sources.
DMARC GeneratorGenerate a DMARC record with the right policy, reporting and alignment settings.
DKIM GeneratorGenerate a DKIM key pair (1024/2048-bit) and the DNS record to publish.
BIMI GeneratorCreate a BIMI record from your logo and VMC certificate URLs.
MTA-STS GeneratorGenerate the MTA-STS DNS record and policy file.
TLS-RPT GeneratorGenerate a TLS-RPT record.