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https://snu.ac.kr

Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
83
GRADE
B
FIX
2
REVIEW
4
PASS
3
INFO
0
Probed from Madrid, Spain
200 OK
Checks
9
3 PASS 4 REVIEW 2 FIX
D
HTTP Probe Timing
Action
Total 2604 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
FIX
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
350 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
310 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
308 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
1.39 s
Total Time Total request time from DNS lookup through full response.
2.60 s

Connection waterfall

DNS Lookup 350 ms TCP Connect 310 ms TLS Handshake 308 ms Server Processing 420 ms Content Transfer 1.22 s
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.

C
IPv6 Readiness
Action
No IPv6 support
REVIEW
No IPv6 support
Info::
No IPv6 (AAAA) records found
IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.
No IPv6 Support
About 40% of internet users have IPv6. Consider adding AAAA records.

IPv6 support is increasingly important for global accessibility. About 40% of internet users have IPv6 connectivity.

Why this matters

No AAAA records — same impact as 'no IPv6 (AAAA) records'; IPv6-preferring clients pay extra latency falling back to IPv4.

Source: Google IPv6 stats

B
Crawlability
robots.txt present, no sitemap
REVIEW
robots.txt present, no sitemap
Info::
robots.txt is present
Got: 1791 bytes
Info::
No sitemap.xml found
A sitemap helps search engines discover and index your pages more efficiently.
Info::
robots.txt does not reference a sitemap
Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

A sitemap helps search engines discover and index your pages more efficiently.

Why this matters

No sitemap.xml — Google relies on crawl-graph discovery alone, slowing indexing of deep or fresh URLs.

Learn more ▾

A sitemap accelerates Google's discovery of new and updated content. Most CMSes auto-generate one; static-site frameworks need a build-step plugin. Reference it from robots.txt and submit in Search Console to confirm Google can fetch it.

Source: sitemaps.org / Google Search Central

Add a 'Sitemap:' directive to robots.txt so search engines can discover your sitemap.

Why this matters

robots.txt omits Sitemap: directive — crawlers must fetch /sitemap.xml by convention; reliable but missing the explicit hint.

Source: sitemaps.org

robots.txt 200 OK
Size 1791 B Sitemaps referenced 0 User-agents Sogou web spider, ias_crawler, CCBot, grapeshot, OpenindexSpider, Bytespider, BLEXBot, AwarioSmartBot, DataForSeoBot, SemrushBot, Buck, AhrefsBot, TurnitinBot, MJ12bot, Baiduspider, *, PetalBot, BomboraBot, Sogou inst spider, proximic, serpstatbot, ClaudeBot, Applebot, YandexCalendar, Paqlebot, GeedoBot, bingbot, Mail.RU_Bot, CriteoBot/0.1, 360Spider, Amazonbot, YandexMobileBot, dotbot, AwarioRssBot, Yisouspider, FemtosearchBot, SeekportBot, GPTBot Blocking No — crawling allowed
User-agent: FemtosearchBot

disallow: /


User-agent: AhrefsBot

disallow: /


User-agent: TurnitinBot

Disallow: /


User-agent: BLEXBot

Disallow: /


User-agent: MJ12bot

Disallow: /


User-agent: PetalBot

Disallow: /


User-agent: Amazonbot

Disallow: /


User-agent: Applebot

Disallow: /


User-agent: YandexCalendar

Disallow: /


User-agent: YandexMobileBot

Disallow: /


User-agent: dotbot

Disallow: /


User-agent: AwarioRssBot

User-agent: AwarioSmartBot

Disallow: /


User-agent: Baiduspider

Disallow: /


User-agent: SemrushBot

Disallow: /


User-agent: PetalBot

Disallow: /


User-agent: BomboraBot

Disallow: /


User-agent: Buck

Disallow: /


User-agent: BLEXBot

Disallow: /


User-agent: SeekportBot

Disallow: /


User-agent: TurnitinBot

Disallow: /


User-agent: Paqlebot

Disallow: /


User-agent: grapeshot

Disallow: /


User-agent: Mail.RU_Bot

Disallow: /


User-agent: GeedoBot

Disallow: /


User-agent: FemtosearchBot

Disallow: /


User-agent: serpstatbot

Disallow: /


User-agent: Amazonbot

Disallow: /


User-agent: CriteoBot/0.1

Disallow: /


User-agent: DataForSeoBot

Disallow: /


User-agent: OpenindexSpider

Disallow: /


User-agent: GPTBot

Disallow: /


User-agent: Baiduspider

User-agent: 360Spider

User-agent: Yisouspider

User-agent: PetalBot

User-agent: Bytespider

User-agent: Sogou web spider

User-agent: Sogou inst spider

Disallow: /


User-agent: proximic

Disallow: /


User-agent: ias_crawler

Disallow: /


User-agent: AwarioRssBot

User-agent: AwarioSmartBot

Disallow: /


User-agent: ClaudeBot

Disallow: /


User-agent: CCBot

Disallow: /


User-agent: bingbot

Crawl-Delay:30

User-agent: Amazonbot

Disallow: /


User-agent: ClaudeBot

Disallow: /



User-agent: *

Allow: /
sitemap.xml No sitemap found

No sitemap found

Adding a sitemap helps search engines discover your pages.

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.snu.ac.kr/
200https://snu.ac.kr/

Inconsistent — duplicate content risk

HTTP → HTTPS

301http://snu.ac.kr/ → https://snu.ac.kr/

Consistent

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

Certificate validity

83
days left
0d 30d 60d 90d+

Recommended actions

  • Submit your domain to hstspreload.org to be added to the Chrome preload list
  • Enable DNSSEC on your domain for DNS spoofing protection
  • Enable OCSP stapling on your TLS server to remove a CA roundtrip and protect user privacy
A
DNS Records
1 A records, 1961 ms lookup
PASS
1 A records, 1961 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 147.46.10.129
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
No IPv6 (AAAA) records
Info::
2 nameserver(s) configured
Got: ercc.snu.ac.kr, hektor.snu.ac.kr
Info::
1 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 (1961 ms)
Slow DNS adds latency to every page load. Consider a faster DNS provider.
Got: 1961 ms
A147.46.10.129
AAAA—
CNAME—
NSercc.snu.ac.kr, hektor.snu.ac.kr
MX
1 aspmx1.gov-dooray.com
TXT
google-site-verification=tnlWpjkEn2QStgwGl-hOaTqajSdFg-lVHwnE2KBCA2M
google-site-verification=R8Pv7GugfmzR6iR0F2Y_2fIPMxmv9KrDXDVbBV8T-Y4
google-site-verification=K0id-g3MG3u-g34h0l35KW98k5AfsWjRptlwnRvL220
google-site-verification=g2SMXdawiwFyaDZbpMTxE_AhnBUYVAFNdWKipq0rjx4
google-site-verification=gDMz4DXUp-UTQAWN0UDm4715AceWtHDVS3Q_Se1uMog
google-site-verification=c-KimjGR4oDTYaHfWp0w_mj0yxzifF3WCx2VT5WsxQs
ZOOM_verify_sInFFu9lRcSsWQAe7XJYnw
google-site-verification=IvY9NupvXzYB_O2r5IFi3xqlwtPONmG0-X3wpUoIFIU
google-site-verification=-fBA2W3mKfRht_TZxHIcimRzOql__0NFHM2JqzXX3Yw
google-site-verification=4mO3mNdxv4eOVmQ8X1DB5uYTc-UpVmXFVIi92q-qLnE
google-site-verification=hScjHXW3wY-A2JgrqYGynN1WlJs7588YRHduPGTzwTw
google-site-verification=sBdCp27WRJCfeTc7QSQpkyPEPSRzviQQtSlzwSXWPm4
google-site-verification=k2mCfO1-nSTuQjX_Uyd3c9pmhZqh5GIO9eWZeUuZphE
google-site-verification=7m2YI4yzcoP6QwSPyIYHLcPNZ3HCRTJq2-QrmizOeck
google-site-verification=QQIpc0PrsAQJSLmmyo3AytDIBIuAt2jDywG6ct-hEr8
google-site-verification=CDK_216Y8Hkn6KSQn4JB8TPiahV_oWr92niG5GQCTAU
google-site-verification=w-i5MwCNo0N-f1lIlQGh3Di86-HpwM4j-WuLeei0KW0
google-site-verification=wI-N4TKgq7jd0MuvlVW6k_79NQiOzgMDCRdM9HCZxAI
SPF v=spf1 include:_spf.snu.ac.kr include:_spf2.snu.ac.kr include:_spf.gov-dooray.co...
google-site-verification=A0SY5QQD77eTEvbF39NKGb7k43LzBCCRKH6cut-xQ8I
google-site-verification=8rfHMBuGQiRxpDoEDUYI6A7V0fY_dangMW5WwLTc844
worksmobile.certification.mv8d3egew4m5eznstx.d4ipppeitg9gda.mqhigo9dj
google-site-verification=Fsh6wHhf1mQr7Ox--G1XbZMog7hqVOuYI_3-OSei4jQ
google-site-verification=wUrbmnBIXpYSDSx-fpit1BGjrOqXwNEMPbRr_Cj4DRo
google-site-verification=87u7Zx7lMCjPBKiXYr1rGKTjiyonTf6DLhTcO_8cI20
LVvILcy1XMRId9XadDTWsdgRUu5HAXCOaBntUHNmm3Y
google-site-verification=Fd9BeooT1__PX-I_qW1Sb1q_1TU2jL85be4WKhuUju8
google-site-verification=iCMaufdYc0-i78p9a9MANBLwBVIWn-aVlR-I7Q8nHME
google-site-verification=xpz1YClg353cwQyMk95OshSyIaiKY81RN7ERDysu-Wc
google-site-verification=olF-5xI1sEzFusIiovXGJdBTCNOUihP4abxk820_HuE
google-site-verification=4Tfs2KIULE37WyBaIwl_W7dbe5lpFiU-kMp-oelm5d0
google-site-verification=N1RIql1C8L1uOberlzh4YOdgsIAZwjsB1iTso84C22M
google-site-verification=XB1AHG5MrRs7KBFNq-2ch69Y8oHYfsAD_tPeOE8C90k
google-site-verification=SNxpYjJls7L_VQPGn9vL4SgtWlGrDBQxSjgvhKfX7nw
google-site-verification=nLt3Pg4ENviBgRu-T6Fk1uXs0EBFJM9I8MA0NIvVbuk
google-site-verification=LbaifWj7Qh6KjKvpc12-6RX-e7NxwuJ8ekn-AuM5PIM
google-site-verification=3NA7QjH2yu4mFw8v97F50-yTv0-_EdKbNoY-usuHq9Y
vc-domain-verify=aichat.snu.ac.kr,6795830f52eafbca89c6
google-site-verification=9L4CxsyRynShaV4R6FuQKnuFZiqsWDdUIKeThvqowEk
google-site-verification=dmK-MGf_aBVYRWcfccMN9BKDMeaHgW_ZzKYpqF47pts
google-site-verification=IIn1aKbVRmLJkKOaJfO6Xs-kL3DaNPuZhZdduandZFg
CAALookup not available with standard resolver
Resolved in 1961 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
No redirects — direct access
PASS
No redirects — direct access
Info::
No redirects — direct access
Got: https://snu.ac.kr

https://snu.ac.kr

987 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://snu.ac.kr200987 msHTTP/1.1
A+
Domain Intelligence
snu.ac.kr — via Megazone(http://HOSTING.KR), hosted on SNU-AS-KR Seoul National University, KR
PASS
snu.ac.kr — via Megazone(http://HOSTING.KR), hosted on SNU-AS-KR Seoul National University, KR
Info::
Registrar: Megazone(http://HOSTING.KR)
Info::
Registrar lock is enabled
Domain cannot be transferred without explicit unlock from the registrar. This protects against unauthorized transfers.
Info::
Hosting: SNU-AS-KR Seoul National University, KR
Got: AS9488
Domain expiry

Unknown

SSL certificate

83 days

Issued by GlobalSign nv-sa

Domain age

Unknown

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

SNU-AS-KR Seoul National University, KR

ASN AS9488

147.46.10.129

Registrar

Megazone(http://HOSTING.KR)

Locked 2 NS records
Expiry timeline
Today
+1 year
SSL expiry Danger zone (≤30 days)
Registrar Megazone(http://HOSTING.KR)
Name Servers ercc.snu.ac.kr, hektor.snu.ac.kr
Hosting
IP Address 147.46.10.129
ASN AS9488 (SNU-AS-KR Seoul National University, KR)
Provider SNU-AS-KR Seoul National University, KR
Data source: whois (1.4s)

Domain cannot be transferred without explicit unlock from the registrar. This protects against unauthorized transfers.

Why this matters

Registrar lock (clientTransferProhibited et al.) prevents unauthorized domain transfers — strongest defense against domain hijacking.

Source: ICANN / domain-security best practice

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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