Infrastructure - https://uni-koeln.de BeaverCheck Audit

D

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.

B

URL Variants

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

REVIEW

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

HTTP version does not redirect to HTTPS

Got: HTTP 0 Expected: 301 redirect to HTTPS

www / non-www

https://www.uni-koeln.de/

200https://uni-koeln.de/

HTTP → HTTPS

http://uni-koeln.de/

HTTP version does not redirect to HTTPS

B

HTTP Probe Timing

Total 1311 ms — DNS, TCP, TLS, TTFB, content transfer breakdown

REVIEW

DNS Lookup

379 ms

TCP Connect

183 ms

TLS Handshake

194 ms

Time to First Byte

944 ms

Total Time

1.31 s

Connection waterfall

DNS Lookup 379 ms TCP Connect 183 ms TLS Handshake 194 ms Server Processing 189 ms Content Transfer 368 ms

B

TLS Certificate Expiry & Recommendations

44 days until leaf cert expires — 4 issues to address

REVIEW

Certificate validity

44

days left

0d 30d 60d 90d+

Recommended actions

Add includeSubDomains to the HSTS directive
Add the preload directive and submit to hstspreload.org once max-age + includeSubDomains are in place
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, 360 ms lookup

PASS

1 A records, 360 ms lookup

Resolves to 1 IPv4 address(es)

Got: 134.95.81.52

Single A record — no DNS redundancy

Multiple A records provide failover if one server goes down.

Has 1 IPv6 (AAAA) record(s)

Got: 2a00:a200:0:2::80

4 nameserver(s) configured

Got: dns-1.dfn.de, noc2.rrz.uni-koeln.de, ns2.netcologne.de, mail1.rrz.uni-koeln.de

2 mail exchanger(s) configured

CAA records not checked

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

SPF record present in TXT

DNS resolution is slow (360 ms)

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

Got: 360 ms

A	134.95.81.52
AAAA	2a00:a200:0:2::80
CNAME	—
NS	dns-1.dfn.de, noc2.rrz.uni-koeln.de, ns2.netcologne.de, mail1.rrz.uni-koeln.de
MX	5 uzk-mail-in-v1.rrz.uni-koeln.de 5 uzk-mail-in-v2.rrz.uni-koeln.de
TXT	MS=ms52477696 google-site-verification=slKdECUuuJ-OuRi4ydQier-7Oj-2Tg_VJyA_kXlUPcU MS=3440AC9067529743C07C50066FE452F078A8500F apple-domain-verification=NPadQczkP1xAfjol apple-domain-verification=fP2uzfO72ptimR1d brevo-code:9aabfa1918b1ee91863be44df6d4b941 adobe-idp-site-verification=4aec6dd94028767a1112cc5f6e09e54597a8b368698e3090e794... cisco-ci-domain-verification=64ff69245d29ac9ceaa0b992ecd76b77594fe0d25edecf3ff8a... apple-domain-verification=XscpNBzRkbfzubTd SPF v=spf1 ip4:134.95.0.0/16 ip4:109.69.68.140 ip6:2a00:a200::/48 include:agenturser...
CAA	Lookup not available with standard resolver

Resolved in 360 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

Got: https://uni-koeln.de

https://uni-koeln.de

734 ms · HTTP/1.1 FINAL

#	URL	Status	Time	Protocol	Server
1	https://uni-koeln.de	200	734 ms	HTTP/1.1	Apache/2.4

A+

IPv6 Readiness

IPv6 reachable (156 ms)

PASS

IPv6 reachable (156 ms)

IPv6 is configured and reachable at 2a00:a200:0:2::80

Got: 156 ms connect

IPv6 Ready

AAAA Records 2a00:a200:0:2::80 Connection Reachable (156 ms)

A+

Crawlability

robots.txt present, sitemap with 519 URLs

PASS

robots.txt present, sitemap with 519 URLs

robots.txt is present

Got: 3014 bytes

sitemap.xml is present

sitemap.xml is valid XML

sitemap.xml contains 519 entries

robots.txt does not reference a sitemap

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 3014 B Sitemaps referenced 0 User-agents GPTBot, * # All other spiders should avoid, ia_archiver, Nuclei Blocking No — crawling allowed

# robots.txt for http://www.uni-koeln.de/
# see <http://www.robotstxt.org/wc/robots.html> for an explanation.
User-agent: *                   # All other spiders should avoid 
Disallow: /cgi-bin/             #     Script files
Disallow: /bin2/                #     Script files
Disallow: /bin3/                #     Script files
Disallow: /kurs-bin/            #     Script files
Disallow: /htdig/               #     Script files
Disallow: /admin/
Disallow: /experimente/
Disallow: /intern/
Disallow: /extern/
Disallow: /kiosk/
Disallow: /rrzk/org/mitarbeiter/
Disallow: /wiso-fak/szyperski/intern/
Disallow: /phil-fak/phil/org/aktuell.htm
Disallow: /med-fak/auge/mitarbeiter.html
Disallow: /rrzk/software/fachspezifisch/Biologie-Genetik/wispact/
Disallow: /google-suche
# Die Custom-Google-Suche wieder neu zu indizieren hätte etwas von
# Rekursion.
Disallow: /tr/
Disallow: /fr/
Disallow: /ar/
Disallow: /es/
# Sprachversionen, die es nie gegeben hat, die aber leider zumindest
# zeitweise im HTML-Code der Startseite von www.uni-koeln.de angepriesen wurden.
##########################################################
# Urspruengliche Komplettblockade zunaechst zumindest fuer Linux- 
# und Microsoft-Doku aufgehoben. CO, 14.07.2005
#
Disallow: /rrzk/Abt-Systeme/     
Disallow: /rrzk/systeme/SFgate/
Disallow: /rrzk/systeme/WWW/
Disallow: /rrzk/systeme/cgi-bin/
Disallow: /rrzk/systeme/dec/
Disallow: /rrzk/systeme/hp/
Disallow: /rrzk/systeme/htbin/
Disallow: /rrzk/systeme/ibm/
Disallow: /rrzk/systeme/intern/
Disallow: /rrzk/systeme/microsoft/
Disallow: /rrzk/systeme/nt/
Disallow: /rrzk/systeme/os2/
Disallow: /rrzk/systeme/sgi/
Disallow: /rrzk/systeme/sun/
Disallow: /rrzk/systeme/archiv
Disallow: /rrzk/systeme/linux/infos/howto
Disallow: /rrzk/server/sundoku/
Disallow: /rrzk/software/dtp/tex/lokal/doc
Disallow: /rrzk/software/tv/tex/lokal/doc
Disallow: /rrzk/software/textverarbeitung/tex/lokal/doc
###########################################################
Disallow: /multimedia-tag/
Disallow: /allgemeines/veranstaltungen/multimedia-tag/
Disallow: /dienste/stat/mon/
Disallow: /wiso-fak/wisostatsem/skripte      # 1.6.04 fuer Christoph Scheicher
Disallow: /wiso-fak/wisostatsem/hauptstudium # scheicher@statistik.uni-koeln.de
Disallow: /wiso-fak/wisostatsem/grundstudium #
Disallow: /ew-fak/Paeda                      # 16.6. fuer Matthias Kleinow
Disallow: /ew-fak/Allg_paeda                 # kleinow@t-online.de
User-agent: ia_archiver
Disallow: /wiso-fak/wisostatsem              # 25.5.04 fuer Christoph Scheicher
Disallow: /med-fak/zahn/vorklinik            # 1.2.05 SW wegen Rekursion, 24.3.05 CO

User-agent: Nuclei
Disallow: /
## WH 2021-06-01, Nach Brute-Force-Angriff

User-Agent: GPTBot
Disallow: /universitaet/aktuell/
Disallow: /en/university/news/
Disallow: /en/universitaet/aktuell/
Disallow: /forschung/forschungsmeldungen/suche-und-archiv/
Disallow: /sites/international/
## WH, 2025-08-29, ChatGPT und der Abruf uralter Pressemeldungen und Co. vom
## TYPO3-Server (pressestelle)

sitemap.xml 200 OK

Type URL Set URLs 519 entries Valid XML Yes

Sample URLs:

A+

Domain Intelligence

uni-koeln.de

PASS

uni-koeln.de

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

Unknown

SSL certificate

44 days

Issued by Let's Encrypt

Domain age

Unknown

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

Unknown

2a00:a200:0:2::80

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 2a00:a200:0:2::80

Data source: whois (1.0s)

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