Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Probed from Madrid, Spain

200 OK

Checks

6 PASS 2 REVIEW 1 FIX

CDN & Delivery

Action

No CDN detected

FIX

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.

DNS Records

Action

1 A records, 278 ms lookup

REVIEW

1 A records, 278 ms lookup

Resolves to 1 IPv4 address(es)

Got: 130.14.29.110

Single A record — no DNS redundancy

Multiple A records provide failover if one server goes down.

Has 1 IPv6 (AAAA) record(s)

Got: 2607:f220:41e:4290::110

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: www.wip.ncbi.nlm.nih.gov

No NS records found

No MX records — email not configured via DNS

CAA records not checked

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

No SPF record found in TXT records

SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.

DNS resolution is slow (278 ms)

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

Got: 278 ms

A	130.14.29.110
AAAA	2607:f220:41e:4290::110
CNAME	www.wip.ncbi.nlm.nih.gov
NS	—
MX	—
TXT	—
CAA	Lookup not available with standard resolver

Resolved in 278 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

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.

SPF helps prevent email spoofing. Add a TXT record starting with 'v=spf1'.

Why this matters

Without SPF, receiving servers can't validate sending IPs — your domain is easier to spoof in phishing.

Learn more ▾

SPF complements DMARC. Both should be published. SPF records list authorized sending IPs (e.g., `v=spf1 include:_spf.google.com ~all` for Google Workspace). After publishing, verify in Google Postmaster Tools or mxtoolbox.

Source: RFC 7208 (SPF)

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

TLS Certificate Expiry & Recommendations

157 days until leaf cert expires — 2 issues to address

REVIEW

Certificate validity

157

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

Got: https://www.ncbi.nlm.nih.gov

https://www.ncbi.nlm.nih.gov

298 ms · HTTP/1.1 FINAL

#	URL	Status	Time	Protocol	Server
1	https://www.ncbi.nlm.nih.gov	200	298 ms	HTTP/1.1	Apache

A+

IPv6 Readiness

IPv6 reachable (99 ms)

PASS

IPv6 reachable (99 ms)

IPv6 is configured and reachable at 2607:f220:41e:4290::110

Got: 99 ms connect

IPv6 Ready

AAAA Records 2607:f220:41e:4290::110 Connection Reachable (99 ms)

A+

Crawlability

robots.txt present, sitemap with 2 URLs

PASS

robots.txt present, sitemap with 2 URLs

robots.txt is present

Got: 10240 bytes

sitemap.xml is present

sitemap.xml is valid XML

sitemap.xml contains 2 entries

Sitemap index with 2 child sitemaps

robots.txt references sitemap

robots.txt 200 OK

Size 10240 B Sitemaps referenced 12 User-agents Googlebot, yacybot, Slurp, Twitterbot, bingbot, Baiduspider, Teleport Pro, Browsershots, Exabot, *, htdig/3.1.6 Blocking No — crawling allowed

# robots.txt - robot exclusion file - back-end server version - no robots!
# ========================================================================
User-agent: htdig/3.1.6
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /mailman
Disallow: /myncbi
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: Baiduspider
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /mailman
Disallow: /myncbi
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: Googlebot
Disallow: /cgi-bin
Disallow: /stat
Disallow: /COG
Disallow: /mailman
Disallow: /sutils
Disallow: /entrez/viewer.fcgi
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /IEB/ToolBox/SB
Disallow: /Structure/dgs
Disallow: /Structure/VA
Disallow: /Structure/cblast/cblast.cgi
Disallow: /Coffeebreak
Disallow: /gorf
Disallow: /mapview
Disallow: /myncbi
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /entrez/eutils
Disallow: /entrez/utils
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/*/bin/
Disallow: /pmc/*/pdf/
Disallow: /pmc/*/equ/
Disallow: /pmc/*.cgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /clone/library/genomic/organisms
Disallow: /sars-cov-2
Allow: /portal/portal3rc.fcgi/*/*.js
Allow: /portal/portal3rc.fcgi/*/*.css

User-agent: Teleport Pro
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: yacybot
Disallow: * 

User-agent: Browsershots
Disallow:
Disallow: /sars-cov-2

User-agent: Slurp
Crawl-delay: 1
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /blast/BlastAlign.cgi
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/*/bin/
Disallow: /pmc/*/pdf/
Disallow: /pmc/*/equ/
Disallow: /pmc/*.cgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /sars-cov-2

User-agent: Twitterbot
Disallow: *
Allow: /pmc/articles
Allow: /books/NBK*

User-agent: Exabot
Disallow: /Structure
Disallow: /mailman
Disallow: /stat
Disallow: /sars-cov-2


User-agent: bingbot
Disallow: /cgi-bin
Disallow: /entrez
Disallow: /stat
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /blast/BlastAlign.cgi
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/*/bin/
Disallow: /pmc/*/pdf/
Disallow: /pmc/*/equ/
Disallow: /pmc/*.cgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /clone/library/genomic/organisms
Disallow: /sars-cov-2
Allow: /portal/portal3rc.fcgi/*/*.js
Allow: /portal/portal3rc.fcgi/*/*.css

User-agent: *
Crawl-delay: 5
Disallow: /cgi-bin
Disallow: /stat
Disallow: /entrez
Disallow: /COG
Disallow: /Entrez
Disallow: /myncbi
Disallow: /mailman
Disallow: /sutils
Disallow: /Taxonomy/Selector
Disallow: /Taxonomy/CommonTree
Disallow: /entrez/sutils
Disallow: /mapview
Disallow: /SAGE
Disallow: /SNP
Disallow: /snp
Disallow: /blast/BlastAlign.cgi 
Disallow: /blast/bl2seq/wblast2.cgi
Disallow: /portal
Disallow: /pmc/utilities/
Disallow: /pmc/issues/
Disallow: /pmc/articles/
Disallow: /pmc/ivip/
Disallow: /pmc/articlerender.fcgi
Disallow: /pmc/pagerender.fcgi
Disallow: /pmc/picrender.fcgi
Disallow: /pmc/tocrender.fcgi
Disallow: /pmc/*report=
Disallow: /pmc/*page=
Disallow: /pmc/articles/*/citedby/
Disallow: /pmc/publisherportal/api/
Disallow: /pmc/publisherportal/application/
Disallow: /pmc/publisherportal/download
Disallow: /pmc/publisherportal/journalmanager/
Disallow: /labs/pmc/
Disallow: /geo/tools
Disallow: /geo/browse 
Disallow: /projects/geo/tools
Disallow: /geo/download
Disallow: /projects/geo/download
Disallow: /projects/gtr/gt
Disallow: /Structure/flink/flink.cgi
Disallow: /Structure/vast/vastsrv.cgi
Disallow: /viewvc
Disallow: /clone/library/genomic/organisms
Disallow: /sars-cov-2
Disallow: /search/?term=
Disallow: /books/?term=
Disallow: /nuccore/?term=
Disallow: /clinvar/?term=
Disallow: /cdd/?term=
Disallow: /gap/?term=
Disallow: /dbvar/?term=
Disallow: /medgen/?term=
Disallow: /snp/?term=
Disallow: /sra/?term=
Disallow: /biocollections/?term=
Disallow: /gtr/?term=
Disallow: /protein/?term=
Disallow: /bioproject/?term=
Disallow: /gene/?term=
Disallow: /biosample/?term=
Disallow: /taxonomy/?term=
Disallow: /ipg/?term=
Disallow: /gds/?term=
Disallow: /geoprofiles/?term=
Disallow: /mesh/?term=
Disallow: /nlmcatalog/?term=
Disallow: /omim/?term=
Disallow: /proteinclusters/?term=
Disallow: /pcassay/?term=
Disallow: /protfam/?term=
Disallow: /pccompound/?term=
Disallow: /pcsubstance/?term=
Disallow: /structure/?term=
Allow: /portal/portal3rc.fcgi/*/*.js
Allow: /portal/portal3rc.fcgi/*/*.css

Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/cdd/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/genome/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/mmdb/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Structure/sitemaps/sparcle/sitemap.xml
Sitemap: https://www.ncbi.nlm.nih.gov/Traces/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/core/assets/osiris/files/sitemap.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=assembly/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=biosystems/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=books/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=cdd/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?p=clinvar/sitemap_index.xml
Sitemap: https://www.ncbi.nlm.nih.gov/escan?

sitemap.xml 200 OK

Type Sitemap Index URLs 2 entries Valid XML Yes

Child Sitemaps:

A+

URL Variants

www/non-www, trailing slash, HTTP→HTTPS

PASS

www/non-www, trailing slash, HTTP→HTTPS

www/non-www redirect configured correctly (preferred: www)

HTTP correctly 301-redirects to HTTPS

www / non-www

200https://www.ncbi.nlm.nih.gov/

301https://ncbi.nlm.nih.gov/

Preferred variant: www

HTTP → HTTPS

301http://www.ncbi.nlm.nih.gov/ → https://www.ncbi.nlm.nih.gov/

Consistent

A+

Domain Intelligence

nih.gov — via get.gov, 28 years, 11 months old, hosted on NIH-NET - National Institutes of Health, US

PASS

nih.gov — via get.gov, 28 years, 11 months old, hosted on NIH-NET - National Institutes of Health, US

Domain registered until Aug 22, 2026 (4 months remaining)

DNSSEC is enabled

Registrar: get.gov

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.

Hosting: NIH-NET - National Institutes of Health, US

Got: AS3527

Domain expiry

5 days

August 22, 2026

SSL certificate

157 days

Issued by GoDaddy.com, Inc.

Domain age

28 years, 11 months

Registered October 2, 1997

DNSSEC

Enabled

Protects against DNS spoofing

Hosting

NIH-NET - National Institutes of Health, US

ASN AS3527

156.40.212.210

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 October 2, 1997 (28 years, 11 months ago)

Expires August 22, 2026 (4 months)

Last Updated March 4, 2026

Name Servers ns.nih.gov, ns2.nih.gov, ns3.nih.gov

DNSSEC Enabled

Registrant REDACTED FOR PRIVACY

Hosting

IP Address 156.40.212.210

ASN AS3527 (NIH-NET - National Institutes of Health, US)

Provider NIH-NET - National Institutes of Health, US

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 309 ms — DNS, TCP, TLS, TTFB, content transfer breakdown

PASS

DNS Lookup

17 ms

TCP Connect

96 ms

TLS Handshake

98 ms

Time to First Byte

310 ms

Total Time

310 ms

Connection waterfall

DNS Lookup 17 ms TCP Connect 96 ms TLS Handshake 98 ms Server Processing 98 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.