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https://cancer.gov

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
91
GRADE
A
FIX
1
REVIEW
2
PASS
6
INFO
0
Probed from Sao Paulo, Brazil
301 Moved Permanently
Checks
9
6 PASS 2 REVIEW 1 FIX
D
CDN & Delivery
Action
No CDN detected
FIX
No CDN detected
Warning::
No CDN detected
A CDN can significantly improve load times for users around the world by caching content at edge nodes closer to them.
No CDN detected

Consider using a CDN to improve global delivery speed and reduce origin load.

B
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
REVIEW
www/non-www, trailing slash, HTTP→HTTPS
Critical::
Both www and non-www versions serve content
Got: Both variants return 200 Expected: One variant 301-redirects to the other
Info::
HTTP correctly 301-redirects to HTTPS

www / non-www

200https://www.cancer.gov/
200https://cancer.gov/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://cancer.gov/ → https://www.cancer.gov/

Consistent

B
TLS Certificate Expiry & Recommendations
142 days until leaf cert expires — 3 issues to address
REVIEW

Certificate validity

142
days left
0d 30d 60d 90d+

Recommended actions

  • Prefer TLS 1.3 — TLS 1.2 is acceptable but TLS 1.3 removes RSA key exchange and improves latency
  • Add includeSubDomains to the HSTS directive
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A
DNS Records
1 A records, 482 ms lookup
PASS
1 A records, 482 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 129.43.254.39
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
Has 1 IPv6 (AAAA) record(s)
Got: 2607:f220:41d:21c1::812b:fe27
Info::
3 nameserver(s) configured
Got: ns.nih.gov, ns2.nih.gov, ns3.nih.gov
Info::
11 mail exchanger(s) configured
Info::
CAA records not checked
CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.
Info::
SPF record present in TXT
Warning::
DNS resolution is slow (482 ms)
Slow DNS adds latency to every page load. Consider a faster DNS provider.
Got: 482 ms
A129.43.254.39
AAAA2607:f220:41d:21c1::812b:fe27
CNAME—
NSns.nih.gov, ns2.nih.gov, ns3.nih.gov
MX
10 nihcesxway4.hub.nih.gov
10 nihcesxwayst06.hub.nih.gov
10 nihcesxwayst04.hub.nih.gov
10 nihcesxway3.hub.nih.gov
10 nihcesxway2.hub.nih.gov
10 nihcesxwayst05.hub.nih.gov
10 nihcesxway.hub.nih.gov
10 nihcesxwayst01.hub.nih.gov
10 nihcesxwayst03.hub.nih.gov
10 nihcesxwayst02.hub.nih.gov
10 nihcesxway5.hub.nih.gov
TXT
o7su2vah6j191i13g6ursf7cns
vaikid9pftv61hpg5b1ll0o1au
SPF v=spf1 include:nih.gov ~all
_0puhfnxczqycfy4u4kmtp0ob01l6ym6
_fcy04k1qajtq6ael7l4pq0ymlwx3u81
_th2y9nk16oxmsorot9619u4ivowe9s1
b26ec43103814a09b7d8d2814fef549c
jrk6xg81sjswjytr4yyqkp6p0d8whjpl
facebook-domain-verification=oc5eiigp252miw61og17pvqvsz4j0t
identrust_validate=KShTAADOwzz+em27pU3J9c6LpvdulIpNLU5CkFAc3LaE
identrust_validate=W64ssWDA7S5UBEN3Lx/2gIfJalru4LeAcpUgqQByIiRY
google-site-verification=7cgm_p1qmwNsajA-7lLR3dcxWTnuLGSnd_1w51qD2M4
google-site-verification=o1YqZG4UHZPWTywBLlIYz3wFyUsHtadoVCjtuW6liPw
google-site-verification=xtotja2khgp7lafpuwbTxpd0-GTHamG6B-n_BlJHaYY
a/MYD7ruuKvW/ln4j50WGOR3Ms9scfgPXKrR4FASC80qVun5eHuz/6s5Xxh/IsTAaDc5+wweHS9ti7aY...
CAALookup not available with standard resolver
Resolved in 482 ms

Multiple A records provide failover if one server goes down.

Why this matters

Single A record means a single point of failure — if that IP goes down, your site is unreachable until DNS TTL expires.

Learn more ▾

Add multiple A records for round-robin failover, or use a managed DNS provider with health-checked failover (Route 53, Cloudflare, NS1). Short TTL (60-300s) lets clients recover faster on outages.

Source: SRE practice / DNS architecture

CAA record lookup requires a specialized DNS resolver. This check will be available in a future update.

Why this matters

Informational: CAA (Certification Authority Authorization) records weren't checked in this scan.

Slow DNS adds latency to every page load. Consider a faster DNS provider.

Why this matters

DNS resolution is slow — anycast DNS providers (Cloudflare, Route 53) typically resolve <50ms globally.

Source: DNS performance benchmarks

A
Redirect Chain
1 redirect(s), 976 ms total
PASS
1 redirect(s), 976 ms total
Info::
Single redirect
Got: https://cancer.gov → https://www.cancer.gov/ (301)
Info::
WWW normalization redirect
Info::
Redirect overhead: 976 ms total
Got: 976 ms

https://cancer.gov

604 ms · HTTP/1.0

301

https://www.cancer.gov/

372 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://cancer.gov301604 msHTTP/1.0BigIP
2https://www.cancer.gov/200372 msHTTP/1.1nginx

See the visual redirect chain in the HTTP Probe tab →

A+
IPv6 Readiness
IPv6 reachable (118 ms)
PASS
IPv6 reachable (118 ms)
Info::
IPv6 is configured and reachable at 2607:f220:41d:21c1::812b:fe27
Got: 118 ms connect
IPv6 Ready
AAAA Records 2607:f220:41d:21c1::812b:fe27 Connection Reachable (118 ms)
A+
Crawlability
robots.txt present, sitemap with 8 URLs
PASS
robots.txt present, sitemap with 8 URLs
Info::
robots.txt is present
Got: 57 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 8 entries
Info::
Sitemap index with 8 child sitemaps
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 57 B Sitemaps referenced 1 User-agents * Blocking No — crawling allowed
sitemap: https://www.cancer.gov/sitemap.xml
User-agent: *
sitemap.xml 200 OK
Type Sitemap Index URLs 8 entries Valid XML Yes
Child Sitemaps:
A+
Domain Intelligence
cancer.gov — via get.gov, 27 years old
PASS
cancer.gov — via get.gov, 27 years old
Info::
Domain registered until Sep 15, 2026 (4 months remaining)
Info::
DNSSEC is enabled
Info::
Registrar: get.gov
Warning::
Registrar lock is NOT enabled
The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.
Domain expiry

62 days

September 15, 2026

SSL certificate

142 days

Issued by DigiCert Inc

Domain age

27 years

Registered August 23, 1999

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

Unknown

2607:f220:41d:21c1::812b:fe27

Registrar

get.gov

Unlocked 3 NS records
Expiry timeline
Today
+1 year
Domain expiry SSL expiry Danger zone (≤30 days)
Recommended actions
  • Renew the domain or enable auto-renewal to prevent accidental expiry
  • Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar get.gov
Created August 23, 1999 (27 years ago)
Expires September 15, 2026 (4 months)
Last Updated April 1, 2026
Name Servers ns.nih.gov, ns2.nih.gov, ns3.nih.gov
DNSSEC Enabled
Registrant REDACTED FOR PRIVACY
Hosting
IP Address 2607:f220:41d:21c1::812b:fe27
Data source: rdap (0.6s)

The domain can be transferred without an unlock step. Enable registrar lock (clientTransferProhibited) in your registrar's control panel to protect against unauthorized or accidental transfers.

Why this matters

Without registrar lock, an attacker who phishes your registrar credentials can transfer the domain in minutes — total brand hijack.

Learn more ▾

Registrar lock (clientTransferProhibited, clientUpdateProhibited, clientDeleteProhibited) requires extra verification before any transfer/update/delete. Every major registrar offers it free. Combined with 2FA on your registrar account, it's the strongest defense against domain hijacking.

Source: ICANN / domain-security best practice

A
HTTP Probe Timing
Total 604 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
124 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
118 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
243 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
605 ms
Total Time Total request time from DNS lookup through full response.
605 ms

Connection waterfall

DNS Lookup 124 ms TCP Connect 118 ms TLS Handshake 243 ms Server Processing 119 ms Content Transfer 0 ms
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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