https://uni-bonn.de
Infrastructure
· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.SCORE
77
GRADE
C
FIX
2
REVIEW
3
PASS
4
INFO
0
Probed from Sao Paulo, Brazil
308 Permanent Redirect
Checks
94 PASS 3 REVIEW 2 FIX
DRedirect ChainAction2 redirect(s), 3001 ms totalFIX
Redirect Chain
Action2 redirect(s), 3001 ms total
2 redirect(s), 3001 ms total
Warning::
2 redirects before reaching final URL
Each redirect adds latency. Try to minimize the chain to 1 hop.
Info::
WWW normalization redirect
Info::
Uses 302 (temporary) redirect
If permanent, use 301 instead.
Got: https://www.uni-bonn.de/
Warning::
Redirect overhead: 3001 ms total
Got: 3001 ms
https://uni-bonn.de
799 ms · HTTP/1.1
308
https://www.uni-bonn.de/
1009 ms · HTTP/1.1
302
https://www.uni-bonn.de/de
1194 ms · HTTP/1.1 FINAL
| # | URL | Status | Time | Protocol | Server |
|---|---|---|---|---|---|
| 1 | https://uni-bonn.de | 308 | 799 ms | HTTP/1.1 | |
| 2 | https://www.uni-bonn.de/ | 302 | 1009 ms | HTTP/1.1 | |
| 3 | https://www.uni-bonn.de/de | 200 | 1194 ms | HTTP/1.1 |
See the visual redirect chain in the HTTP Probe tab →
Each redirect adds latency. Try to minimize the chain to 1 hop.
Why this matters
Redirect chain — each hop adds latency; combine into one redirect where possible.
Source: Google Search Central / web.dev
If permanent, use 301 instead.
Why this matters
302 (Found) is for genuinely temporary redirects — if this redirect is permanent, switch to 301 to preserve SEO equity.
Learn more ▾ ▴
Search engines treat 302 as temporary, keeping the original URL indexed and not transferring full link equity to the destination. Use 301 (Moved Permanently) for permanent redirects (HTTP→HTTPS, www-vs-non-www, URL restructures).
Source: Google Search Central
DCDN & DeliveryActionNo CDN detectedFIX
CDN & Delivery
ActionNo CDN detected
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.
CIPv6 ReadinessActionNo IPv6 supportREVIEW
IPv6 Readiness
ActionNo IPv6 support
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
BCrawlabilityrobots.txt present, sitemap with 0 URLsREVIEW
Crawlability
robots.txt present, sitemap with 0 URLs
robots.txt present, sitemap with 0 URLs
Info::
robots.txt is present
Got: 10240 bytes
Info::
sitemap.xml is present
Warning::
sitemap.xml contains invalid XML
Search engines may not be able to parse the sitemap. Fix XML validation errors.
Warning::
sitemap.xml is empty — no URLs found
An empty sitemap provides no value. Add <url> entries for your pages.
Info::
robots.txt references sitemap
Search engines may not be able to parse the sitemap. Fix XML validation errors.
Why this matters
An unparseable sitemap is silently ignored by Google — the URLs it advertises are never queued for crawl.
Learn more ▾ ▴
Google's sitemap parser is strict about XML validity. A single unescaped `&` or unclosed tag invalidates the whole file. Run your sitemap through a validator (Search Console's Sitemaps report flags it) and fix the offending entry. Most generators escape correctly; mistakes usually come from manually-written entries.
Source: sitemaps.org / Google Search Central
An empty sitemap provides no value. Add <url> entries for your pages.
Why this matters
An empty sitemap signals 'no content to index' to Google — actively harmful versus having no sitemap at all.
Learn more ▾ ▴
Google compares URLs in the sitemap against URLs it has crawled. An empty sitemap on a site with thousands of pages signals abandonment. Either populate it correctly (most CMSes auto-generate) or delete the file and let Google crawl normally.
Source: Google Search Central / sitemaps.org
robots.txt 200 OK
Size 10240 B Sitemaps referenced 1 User-agents BluechipBacklinks, *, Googlebot Blocking No — crawling allowed
Sitemap: https://www.uni-bonn.de/sitemap.xml.gz
# Define access-restrictions for robots/spiders
# http://www.robotstxt.org/wc/norobots.html
User-agent: BluechipBacklinks
Disallow: /
# By default we allow robots to access all areas of our site
# already accessible to anonymous users
User-agent: *
Crawl-delay: 1
Disallow:
# Add Googlebot-specific syntax extension to exclude forms
# that are repeated for each piece of content in the site
# the wildcard is only supported by Googlebot
# http://www.google.com/support/webmasters/bin/answer.py?answer=40367&ctx=sibling
User-Agent: Googlebot
Allow: *regulations_overview
Disallow: /*?
Disallow: /*atct_album_view$
Disallow: /*folder_factories$
Disallow: /*folder_summary_view$
Disallow: /*login_form$
Disallow: /*mail_password_form$
Disallow: /@@search
Disallow: /*search_rss$
Disallow: /*sendto_form$
Disallow: /*summary_view$
Disallow: /*thumbnail_view$
Disallow: /*view$
Disallow: */search
Disallow: */de/international/listen/copy_of_webseiten-6-4
Disallow: */de/international/listen/copy_of_kurz-url-6-4
Disallow: */de/international/listen/copy_of_kurz-url-6-1
Disallow: */de/international/listen/copy_of_kurz-url-6-3
Disallow: */de/international/listen/copy_of_kurz-url-6-cu
Disallow: */de/international/listen/copy_of_kurz-url
Disallow: */de/international/listen/veranstaltungshinweise-io
Disallow: */de/international/listen/kurz-url
Disallow: */de/forschung-lehre/promovierende-und-postdocs/doc_klickanleitung
Disallow: */de/international/anleitung-perfekte-video-selfies-mit-dem-smartphone-fuer-instagram
Disallow: */en/international/anleitung-perfekte-video-selfies-mit-dem-smartphone-fuer-instagram
Disallow: */de/international/anleitung-video-selfies
Disallow: */en/international/guide-video-selfies
Disallow: */de/forschung-lehre/forschung-und-lehre-medien/promovierende-und-postdocs-medien/compliance-reihev2_seite_1.png
Disallow: */en/international/international-profile/partnerships-and-cooperations-worldwide/university-partnerships/global-universities-for-societal-impact-gusi/downloads
Disallow: */de/international/listen/copy_of_veranstaltungen-6-3
Disallow: */de/international/listen/copy_of_veranstaltungen-6-2-6-3-club
Disallow: */de/international/listen/internkulturelle-trainings-6-2-6-3
Disallow: */de/forschung-lehre/promovierende-und-postdocs/eine-promotion-planen/spps/spps
Disallow: */de/studium/organisation-des-studiums/bonner-studienbegleitprogramm-be-strong/marketing-bergfest
Disallow: */de/forschung-lehre/transfercenter-enacom/gruenden/exist-women/bewerbung-exist-women-2025-26
Disallow: */en/research-and-teaching/transfer-center-enacom/founding-a-company/application-exist-women-2025-26
Disallow: */de/universitaet/medien-universitaet/medien-presse-kommunikation/medien-wissenschaft-fuer-alle
Disallow: */en/research-and-teaching/support-for-researchers-and-teachers/research-funding/university-grants/universitaere-foerderlinien
Disallow: */de/international/listen/copy_of_veranstaltungen-6-2
Disallow: */de/universitaet/ueber-die-uni/digitalisierung-1/neues-rund-um-digitalisierung
Disallow: */de/international/listen/kurz-url-io
Disallow: */en/studying/study-and-internship-abroad/ordner/download
Disallow: */de/studium/organisation-des-studiums/bonner-studienbegleitprogramm-be-strong/marketing-be-strong
Disallow: */de/studium/organisation-des-studiums/studienverlauf/marketing-bergfest
Disallow: */de/universitaet/presse-kommunikation/publikationen/forsch/a/moderne-methoden-fuer-alte-und-neue-funde/abb01_klein2.jpg
Disallow: */de/universitaet/presse-kommunikation/publikationen/forsch/a/moderne-methoden-fuer-alte-und-neue-funde
Disallow: */de/studium/studium-und-praktikum-im-ausland/erfahrungsberichte/berichte/ub-fokusseite
Disallow: */de/studium/studium-und-praktikum-im-ausland/erfahrungsberichte/berichte/promos/praktikum/back
Disallow: */de/international/bonn-university-ambassadors/bonn-university-ambassador-surveys
Disallow: */de/universitaet/presse-kommunikation/publikationen/newsletter-links
Disallow: */de/international/bonn-university-ambassadors/bonn-university-ambassador-surveys/bonn-university-ambassador-survey
Disallow: */de/international/listen/copy_of_webseiten-mit-bewerbungsfristen
Disallow: */de/international/listen/copy_of_webseiten-mit-zahlen-und-fakten
Disallow: */de/international/listen/copy_of_webseiten-6-2
Disallow: */de/international/listen/copy_of_webseiten-6-1
Disallow: */en/international/100-years-daad/guide-video-selfies
Disallow: */de/international/testflaeche/copy_of_anmeldung-internkulturelles-training
Disallow: */de/international/solidaritaet-mit-israel/solidaritaet-mit-israel
Disallow: */en/international/solidarity-with-israel/solidarity-with-israel
Disallow: */de/international/listen/copy_of_webseiten-mit-bewerbungsfristen-6-2
Disallow: */de/international/listen/copy_of_webseiten-mit-zahlen-und-fakten-6-2
Disallow: */de/international/listen/copy_of_webseiten-mit-bewerbungsfristen-6-3
Disallow: */de/international/listen/copy_of_webseiten-mit-zahlen-und-fakten-6-3
Disallow: */en/international/anmeldung-internkulturelles-training-erweitert
Disallow: */en/international/copy_of_registration-intercultural-training
Disallow: */en/international/registration-intercultural-training-extended
Disallow: */de/international/listen/copy_of_webseiten-6-3
Disallow: */de/international/listen/copy_of_downloads-webseiten-6-2
Disallow: */de/international/listen/copy_of_downloads-webseiten-6-3
Disallow: */de/international/100-jahre-daad/anleitung-video-selfies
Disallow: */de/universitaet/presse-kommunikation/publikationen/forsch/copy_of_forsch-2025-02/forsch-artikel
Disallow: */de/universitaet/presse-kommunikation/publikationen/forsch/copy_of_forsch-2025-02/artikel
Disallow: */de/international/listen/copy_of_downloads-webseiten-6-1
Disallow: */en/news/weibliche-karrieren-in-forschung-und-lehre-foerdern/interview-mit-jun-prof-dr-elena-s-reckzeh
Disallow: */de/international/testflaeche/copy_of_anmeldung-internkulturelles-training-erweitert
Disallow: */de/international/testflaeche/anmeldung-internkulturelles-training
Disallow: */en/international/testflache/copy_of_registration-intercultural-training-extended
Disallow: */en/international/testflache/copy_of_registration-intercultural-training-extended-in-person-26mmdd
Disallow: */de/international/testflaeche/copy_of_anmeldung-internkulturelles-training-online-26mmdd
Disallow: */de/international/testflaeche/anmeldung-internkulturelles-training-online-26mmdd
Disallow: */de/international/testflaeche/anmeldung-internkulturelles-training-praesenz-26mmdd
Disallow: */en/international/testflache/registration-intercultural-training-extended-in-person-26mmdd
Disallow: */en/international/testflache/registration-intercultural-training-extended-online-26mmdd
Disallow: */en/international/campus-international/intercultural-trainings/registration-intercultural-training-extended-in-person-26mmdd
Disallow: */en/international/campus-international/intercultural-trainings/registration-260320
Disallow: */de/international/campus-international/interkulturelle-trainings/anmeldung-260424
Disallow: */en/international/campus-international/intercultural-trainings/registration-intercultural-training-online-26mmdd
Disallow: */en/international/campus-international/intercultural-trainings/20260508-registration
Disallow: */de/international/campus-international/interkulturelle-trainings/anmeldung-internkulturelles-training-praesenz-26mmdd
Disallow: */de/international/campus-international/interkulturelle-trainings/anmeldung-internkulturelles-training-online-26mmdd
Disallow: */en/international/campus-international/intercultural-trainings/20260703-registration
Disallow: */en/international/campus-international/intercultural-trainings/registration-intercultural-training-in-person-26mmdd
Disallow: */en/international/campus-international/intercultural-trainings/20260710-registration
Disallow: */en/international/campus-international/intercultural-trainings/20260424-anmeldung
Disallow: */en/international/campus-international/intercultural-trainings/20260522-anmeldung
Disallow: */en/international/campus-international/intercultural-trainings/20260619-anmeldung
Disallow: */en/international/campus-international/registration-form-gep-get-together-2026
Disallow: */de/international/listen/copy_of_veranstaltungen-io
Disallow: */de/international/news-international
Disallow: */de/international/internationales-profil/erasmus/ka2
Disallow: */de/studium/studium-und-praktikum-im-ausland/messe-supa/archiv/downloads-archiv
Disallow: */de/universitaet/presse-kommunikation/presseservice/archiv-pressemitteilungen/2013/138-2013
Disallow: */de/universitaet/test-ordner-kim/test-medienordner-kim
Disallow: */de/studium/studienorientierung-und-uni-bonn-entdecken/kennenlern-und-orientierungsangebote/marketing-bonner-hochschultage
Disallow: */de/studium/studienorientierung-und-uni-bonn-entdecken/kennenlern-und-orientierungsangebote/marketing-wochen-der-studienorientierung
Disallow: */de/studium/studienorientierung-und-uni-bonn-entdecken/junge-uni/veranstaltungen-und-wettbewerbe/wissenschaftsrallyes/hofgarten/wissenschaftsrallye-rund-um-den-hofgarten-2026-1
Disallow: */de/studium/testordner
Disallow: */100-jahre-daad
Disallow: */100-years-daad
Disallow: */gestaltung-international-office
Disallow: */sommer
Disallow: */de/universitaet/ueber-die-uni/nachhaltige-uni/eigene-nachrichten/neues-leben-fuer-alte-schreibtische/neues-leben-fuer-alte-schreibtische-universitaet-bonn-schont-ressourcen-und-nutzt-moebel-aus-dem-hauptgebaeude-weiter-forsch-gelesen-2025-02
Disallow: */de/universitaet/ueber-die-uni/nachhaltige-uni/eigene-nachrichten/nachhaltig-bauen-fuer-die-forschung/nachhaltig-bauen-fuer-die-forschung-forsch-gelesen-2025-02
Disallow: */de/universitaet/organisation/universitaetsverwaltung/dezernat-3-personalmangement/abteilung-3-1-professoren-berufungsverfahren
Disallow: */de/universitaet/organisation/universitaetsverwaltung/dezernat-3-personalmangement/dezernat-3-personalmanagement_alt
Disallow: */de/universitaet/organisation/universitaetsverwaltung/dezernat-3-personalmangement/abteilung-3-
sitemap.xml 200 OK
Type URL Set URLs 0 entries Valid XML No
BTLS Certificate Expiry & Recommendations85 days until leaf cert expires — 4 issues to addressREVIEW
TLS Certificate Expiry & Recommendations
85 days until leaf cert expires — 4 issues to address
Certificate validity
85
days left
0d 30d 60d 90d+
Recommended actions
- Extend HSTS max-age to at least 31536000 (1 year) to meet the preload list criteria
- Add includeSubDomains to the HSTS directive
- 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
ADNS Records1 A records, 204 ms lookupPASS
DNS Records
1 A records, 204 ms lookup
1 A records, 204 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 131.220.250.29
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
No IPv6 (AAAA) records
Info::
4 nameserver(s) configured
Got: dns1.uni-bonn.de, unibn-dns.uni-koeln.de, dns3.uni-bonn.de, dns2.uni-bonn.de
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 (204 ms)
Slow DNS adds latency to every page load. Consider a faster DNS provider.
Got: 204 ms
| A | 131.220.250.29 |
| AAAA | — |
| CNAME | — |
| NS | dns1.uni-bonn.de, unibn-dns.uni-koeln.de, dns3.uni-bonn.de, dns2.uni-bonn.de |
| MX | 10 esa3.rhrz.uni-bonn.de 10 esa2.rhrz.uni-bonn.de 10 esa1.rhrz.uni-bonn.de |
| TXT | HARICA-T6jUW4oLmBmgQ45i1F2 SPF v=spf1 redirect=_spf.uni-bonn.de HARICA-rHcUdgC1W9geYonH7fP google-site-verification=-ibadjbrMpJZNJXoDcRi1rgwNv3hAIHo4WpDeQ8cje8 |
| CAA | Lookup not available with standard resolver |
Resolved in 204 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+URL Variantswww/non-www, trailing slash, HTTP→HTTPSPASS
URL Variants
www/non-www, trailing slash, HTTP→HTTPS
www/non-www, trailing slash, HTTP→HTTPS
Info::
www/non-www redirect configured correctly (preferred: non-www)
Info::
HTTP correctly 301-redirects to HTTPS
www / non-www
302https://www.uni-bonn.de/
200https://uni-bonn.de/
Preferred variant: non-www
HTTP → HTTPS
301http://uni-bonn.de/ → https://uni-bonn.de/
Consistent
A+Domain Intelligenceuni-bonn.de — hosted on DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DEPASS
Domain Intelligence
uni-bonn.de — hosted on DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE
uni-bonn.de — hosted on DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE
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.
Info::
Hosting: DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE
Got: AS680
Domain expiry
Unknown
SSL certificate
85 days
Issued by Let's Encrypt
Domain age
Unknown
DNSSEC
Status unknown
Protects against DNS spoofing
Hosting
DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE
ASN AS680
131.220.250.29
Registrar
Registrar unknown
Unlocked Name servers unknown
Expiry timeline
Today
+1 year
SSL expiry Danger zone (≤30 days)
Recommended actions
- Enable registrar lock (clientTransferProhibited) to block unauthorized domain transfers
Registrar
Hosting
IP Address 131.220.250.29
ASN AS680 (DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE)
Provider DFN Verein zur Foerderung eines Deutschen Forschungsnetzes e.V., DE
Data source: whois (1.5s)
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
AHTTP Probe TimingTotal 796 ms — DNS, TCP, TLS, TTFB, content transfer breakdownPASS
HTTP Probe Timing
Total 796 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
197 msTCP Connect TCP Connect — time to establish a TCP connection to the server.
197 msTLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
203 msTime to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
796 msTotal Time Total request time from DNS lookup through full response.
796 msConnection waterfall
DNS Lookup 197 ms TCP Connect 197 ms TLS Handshake 203 ms Server Processing 198 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.