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https://medlineplus.gov

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
92
GRADE
A
FIX
0
REVIEW
3
PASS
6
INFO
0
Probed from Amsterdam, Netherlands
200 OK
Checks
9
6 PASS 3 REVIEW
B
DNS Records
4 A records, 253 ms lookup
REVIEW
4 A records, 253 ms lookup
Info::
Resolves to 4 IPv4 address(es)
Got: 18.239.18.98, 18.239.18.9, 18.239.18.15, 18.239.18.110
Info::
Has 8 IPv6 (AAAA) record(s)
Got: 2600:9000:2449:5a00:1:6b7c:7400:93a1, 2600:9000:2449:4000:1:6b7c:7400:93a1, 2600:9000:2449:9c00:1:6b7c:7400:93a1, 2600:9000:2449:9800:1:6b7c:7400:93a1, 2600:9000:2449:7800:1:6b7c:7400:93a1, 2600:9000:2449:e200:1:6b7c:7400:93a1, 2600:9000:2449:0:1:6b7c:7400:93a1, 2600:9000:2449:ee00:1:6b7c:7400:93a1
Warning::
CNAME record at zone apex
A CNAME at the zone apex can break MX and NS records. Use ALIAS/ANAME or A records instead.
Got: medlineplus.awsprod.nlm.nih.gov
Info::
3 nameserver(s) configured
Got: gslb01.nlm.nih.gov, gslb02.nlm.nih.gov, gslb03.nlm.nih.gov
Info::
3 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 (253 ms)
Slow DNS adds latency to every page load. Consider a faster DNS provider.
Got: 253 ms
A18.239.18.98, 18.239.18.9, 18.239.18.15, 18.239.18.110
AAAA2600:9000:2449:5a00:1:6b7c:7400:93a1, 2600:9000:2449:4000:1:6b7c:7400:93a1, 2600:9000:2449:9c00:1:6b7c:7400:93a1, 2600:9000:2449:9800:1:6b7c:7400:93a1, 2600:9000:2449:7800:1:6b7c:7400:93a1, 2600:9000:2449:e200:1:6b7c:7400:93a1, 2600:9000:2449:0:1:6b7c:7400:93a1, 2600:9000:2449:ee00:1:6b7c:7400:93a1
CNAMEmedlineplus.awsprod.nlm.nih.gov
NSgslb01.nlm.nih.gov, gslb02.nlm.nih.gov, gslb03.nlm.nih.gov
MX
10 nihcesxway5.hub.nih.gov
10 nihcesxway4.hub.nih.gov
10 nihcesxway3.hub.nih.gov
TXT
SPF v=spf1 include:nih.gov ~all
7ae5d325d5804e5893a3bf186eed3bd6
v=DKIM1; k=rsa; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAp9GukUx8QLisQTr4nd...
CAALookup not available with standard resolver
Resolved in 253 ms

A CNAME at the zone apex can break MX and NS records. Use ALIAS/ANAME or A records instead.

Why this matters

CNAME at the apex (example.com) breaks every other apex record (MX, TXT, NS) — DNS-protocol violation per RFC 1034.

Learn more ▾

RFC 1034 forbids CNAME alongside other records at the same name. Some DNS providers offer ALIAS / ANAME / flattened-CNAME records that work around this — use those instead. Otherwise apex-level CNAME breaks email (no MX), domain ownership verification (no TXT), and more.

Source: RFC 1034

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

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.medlineplus.gov/
200https://medlineplus.gov/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://medlineplus.gov/ → https://medlineplus.gov/

Consistent

B
TLS Certificate Expiry & Recommendations
284 days until leaf cert expires — 2 issues to address
REVIEW

Certificate validity

284
days left
0d 30d 60d 90d+

Recommended actions

  • Submit your domain to hstspreload.org to be added to the Chrome preload list
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A+
Redirect Chain
No redirects — direct access
PASS
No redirects — direct access
Info::
No redirects — direct access
Got: https://medlineplus.gov

https://medlineplus.gov

22 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://medlineplus.gov20022 msHTTP/1.1AmazonS3
A+
IPv6 Readiness
IPv6 reachable (1 ms)
PASS
IPv6 reachable (1 ms)
Info::
IPv6 is configured and reachable at 2600:9000:2449:5a00:1:6b7c:7400:93a1, 2600:9000:2449:4000:1:6b7c:7400:93a1, 2600:9000:2449:9c00:1:6b7c:7400:93a1, 2600:9000:2449:9800:1:6b7c:7400:93a1, 2600:9000:2449:7800:1:6b7c:7400:93a1, 2600:9000:2449:e200:1:6b7c:7400:93a1, 2600:9000:2449:0:1:6b7c:7400:93a1, 2600:9000:2449:ee00:1:6b7c:7400:93a1
Got: 1 ms connect
IPv6 Ready
AAAA Records 2600:9000:2449:5a00:1:6b7c:7400:93a1, 2600:9000:2449:4000:1:6b7c:7400:93a1, 2600:9000:2449:9c00:1:6b7c:7400:93a1, 2600:9000:2449:9800:1:6b7c:7400:93a1, 2600:9000:2449:7800:1:6b7c:7400:93a1, 2600:9000:2449:e200:1:6b7c:7400:93a1, 2600:9000:2449:0:1:6b7c:7400:93a1, 2600:9000:2449:ee00:1:6b7c:7400:93a1 Connection Reachable (1 ms)
A+
Crawlability
robots.txt present, sitemap with 25430 URLs
PASS
robots.txt present, sitemap with 25430 URLs
Info::
robots.txt is present
Got: 447 bytes
Info::
sitemap.xml is present
Info::
sitemap.xml is valid XML
Info::
sitemap.xml contains 25430 entries
Info::
robots.txt references sitemap
robots.txt 200 OK
Size 447 B Sitemaps referenced 1 User-agents * Blocking No — crawling allowed
Sitemap: https://medlineplus.gov/sitemap.xml
User-agent: *
Disallow: /URLchecker/
Disallow: /usp/
Disallow: /cgi/
Disallow: /logs/
Disallow: /glftp/
Disallow: /feeds/topics/
Disallow: /groupfeeds/
Disallow: /spanish/feeds/topics/
Disallow: /spanish/groupfeeds/
Disallow: /xml/
Disallow: /xml/vocabulary/
Disallow: /scwidget/topsearch.html
Disallow: /spanish/scwidget/topsearch.html
Disallow: /tutorials/*.swf$
Disallow: /spanish/tutorials/*.swf$
sitemap.xml 200 OK
Type URL Set URLs 25430 entries Valid XML Yes
Sample URLs:
A+
Domain Intelligence
medlineplus.gov — via get.gov, 26 years, 7 months old
PASS
medlineplus.gov — via get.gov, 26 years, 7 months 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

284 days

Issued by Amazon

Domain age

26 years, 7 months

Registered February 4, 2000

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

Unknown

2600:9000:2449:f600:1:6b7c:7400:93a1

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 February 4, 2000 (26 years, 7 months ago)
Expires September 15, 2026 (4 months)
Last Updated October 20, 2025
Name Servers gslb01.nlm.nih.gov, gslb02.nlm.nih.gov, gslb03.nlm.nih.gov
DNSSEC Enabled
Registrant REDACTED FOR PRIVACY
Hosting
IP Address 2600:9000:2449:f600:1:6b7c:7400:93a1
Data source: rdap (0.7s)

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 477 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
468 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
1 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
4 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
477 ms
Total Time Total request time from DNS lookup through full response.
478 ms

Connection waterfall

DNS Lookup 468 ms TCP Connect 1 ms TLS Handshake 4 ms Server Processing 4 ms Content Transfer 1 ms
A+
CDN & Delivery
AWS CloudFront (Hit from cloudfront)
PASS
AWS CloudFront (Hit from cloudfront)
Info::
Site is served via AWS CloudFront CDN (edge: AMS58-P6)
Got: x-amz-cf-id: YgpFbm33dItUAjU8TXaSDk_ryKslgf4k1fhsHs0la9vGp2a1ih8Fbg==
Info::
CDN cache status: Hit from cloudfront
CDN Detected: AWS CloudFront
Provider AWS CloudFront Cache Status Hit from cloudfront Evidence x-amz-cf-id: YgpFbm33dItUAjU8TXaSDk_ryKslgf4k1fhsHs0la9vGp2a1ih8Fbg==
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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