kayak.com
HTTPS & TLS
88/100A- HSTS0/4
No HSTS: a visitor's first request can be downgraded to plain HTTP.
- HTTPS certificateLet's Encrypt10/10
HTTPS with a valid certificate from Let's Encrypt.
- Certificate expiry444/4
The certificate is valid for another 44 days.
- TLS versionTLS 1.34/4
Negotiates TLS 1.3, the current protocol: faster handshakes, forward secrecy always.
- Old protocols3/3
Refuses the retired TLS 1.0 and 1.1.
- Key strengthRSA 20482/2
A strong key: RSA 2048.
- HTTP → HTTPS3013/3
http:// redirects straight to https://.
- HTTP/2 and HTTP/3HTTP/22/2
HTTP/2.
DNS
79/100B- DNSSEC0/3
Not signed with DNSSEC: a forged DNS answer for the domain cannot be told from the real one.
- Name servers34/4
3 name servers for the domain.
- Name servers answer3/35/5
Every name server answers for the domain, with the same version of the zone.
- CAA recordsglobalsign.com, letsencrypt.org, pki.goog, ssl.com, amazon.com, comodoca.com, digicert.com, awstrust.com2/2
CAA records name the authorities allowed to issue its certificates.
- MTA-STS0/2
No MTA-STS: mail to the domain can be read in transit by stripping its encryption.
- TLS reporting0/0.5
No TLS reporting: failed encrypted deliveries go unnoticed.
- SPF~all4/5
SPF lists the servers allowed to send its mail and marks the rest as suspicious (~all).
- DMARCreject7/7
DMARC tells receivers to reject mail that fakes the domain (p=reject).
- DKIMgoogle2/2
A DKIM key is published (selector google), so its mail can be signed.
Web & network
88/100A- Content Security Policypartial1.5/3
A Content Security Policy is sent, but it does not limit scripts.
- Permissions-Policy0/0.5
No Permissions-Policy: embedded content may ask for camera, microphone or location.
- X-Content-Type-Options2/2
X-Content-Type-Options: nosniff stops browsers guessing file types.
- Framing2/2
Other sites cannot frame its pages (clickjacking protection).
- Referrer-Policyorigin-when-cross-origin0.5/0.5
Referrer-Policy limits what other sites learn about where visitors came from.
- IPv64/4
kayak.com is reachable over IPv6 as well as IPv4.
- RPKIvalid4/4
The route to the website is RPKI-valid: networks can reject hijacked announcements of it.
Dependencies
100/100A+- DNS providersfoundationdns.com, foundationdns.net, foundationdns.org5/5
DNS is served by 3 providers: one can fail without taking the domain offline.
- One company for everything5/5
The website, DNS and email do not all hang on one company.
Who runs it
- Website
- Fastly
- DNS
- foundationdns.comfoundationdns.netfoundationdns.org
- Proofpoint
Routes
- 151.101.128.0/22AS54113RPKI valid
- 2a04:4e42:200::/48AS54113RPKI valid
Name servers
- blue.foundationdns.comfoundationdns.comAS13335
- blue.foundationdns.netfoundationdns.netAS13335
- blue.foundationdns.orgfoundationdns.orgAS13335
README badge
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What is graded
A valid certificate (an invalid one means F), its expiry against its lifetime, TLS 1.3, no TLS 1.0/1.1 (else at most B), http:// sent straight to https://, HSTS, HTTP/2.
At least two name servers that all answer and agree, DNSSEC, CAA records, and a registration that is not about to expire.
SPF, a DMARC policy that rejects forgeries (none means at most B), MTA-STS and TLS reporting for domains that take mail, DKIM at common selectors.
Content Security Policy, nosniff, framing protection, Referrer- and Permissions-Policy, IPv6, and an RPKI-valid route (invalid means at most C).
DNS from more than one provider, and the website, DNS and email not all with one company.
A+ 95–100 · A 85–94 · B 75–84 · C 65–74 · D 50–64 · F below 50