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Infrastructure

· 9 checks — DNS, redirects, IPv6, crawlability, URL variants, and domain intelligence rolled into one auditable list.
SCORE
85
GRADE
B
FIX
1
REVIEW
3
PASS
5
INFO
0
Probed from Madrid, Spain
302 Found
Checks
9
5 PASS 3 REVIEW 1 FIX
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
Crawlability
Action
robots.txt present, sitemap with 0 URLs
REVIEW
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 does not reference a sitemap
Add a 'Sitemap:' directive to robots.txt so search engines can discover your 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

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 10240 B Sitemaps referenced 0 User-agents Blocking No — crawling allowed
<!doctype html>
<html lang="de-DE">
	<head>
	<meta charset="utf-8">
	<meta http-equiv="x-ua-compatible" content="ie=edge">
	<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
	<meta property="fb:pages" content="113785728679660">
	<title>Johannes Gutenberg-Universität Mainz</title>
<meta name='robots' content='max-image-preview:large' />
<link rel="alternate" hreflang="en" href="https://cms.zdv.uni-mainz.de/startseite/en/" />
<link rel="alternate" hreflang="de" href="https://cms.zdv.uni-mainz.de/startseite/" />
<link rel="alternate" hreflang="x-default" href="https://cms.zdv.uni-mainz.de/startseite/" />
<link rel='dns-prefetch' href='//cms.zdv.uni-mainz.de' />
<link rel='dns-prefetch' href='//cms-cdn.zdv.uni-mainz.de' />
<link rel="alternate" title="oEmbed (JSON)" type="application/json+oembed" href="https://www.uni-mainz.de/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fwww.uni-mainz.de%2F" />
<link rel="alternate" title="oEmbed (XML)" type="text/xml+oembed" href="https://www.uni-mainz.de/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fwww.uni-mainz.de%2F&#038;format=xml" />
<style id='wp-img-auto-sizes-contain-inline-css' type='text/css'>
img:is([sizes=auto i],[sizes^="auto," i]){contain-intrinsic-size:3000px 1500px}
/*# sourceURL=wp-img-auto-sizes-contain-inline-css */
</style>
<link rel='stylesheet' id='jgu-theme-default-css' href='https://www.uni-mainz.de/wp-content/themes/jgu-theme/dist/main.css?ver=10e130b278ba0a8b7f5b' type='text/css' media='all' />
<link rel='stylesheet' id='line-awesome-css' href='https://cms-cdn.zdv.uni-mainz.de/css/line-awesome.min.css?ver=1.3.0' type='text/css' media='all' />
<link rel='stylesheet' id='wp-block-library-css' href='https://www.uni-mainz.de/wp-includes/css/dist/block-library/style.min.css?ver=6.9.4' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-fis_styles-css' href='https://cms.zdv.uni-mainz.de/startseite/wp-content/plugins/jgu-fis/dist/styles/blocks/styles.css?ver=1642102651' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-jogustine_styles-css' href='https://cms.zdv.uni-mainz.de/startseite/wp-content/plugins/jgu-jogustine/dist/styles/blocks/styles.css?ver=1642102651' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-base_frontend.css-css' href='https://www.uni-mainz.de/wp-content/plugins/jgu-base/dist/frontend.css?ver=1776761622' type='text/css' media='all' />
<link rel='stylesheet' id='line-awesome-editor-css' href='https://cms-cdn.zdv.uni-mainz.de/css/line-awesome.min.css?ver=6.9.4' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-fis-css' href='https://cms.zdv.uni-mainz.de/startseite/wp-content/plugins/jgu-fis/dist/styles/frontend.css?ver=1642102651' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-jogustine-css' href='https://cms.zdv.uni-mainz.de/startseite/wp-content/plugins/jgu-jogustine/dist/styles/frontend.css?ver=1695716747' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-navigation-structure_frontend.css-css' href='https://www.uni-mainz.de/wp-content/plugins/jgu-navigation-structure/dist/frontend.css?ver=1702383773' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-tools-css' href='https://cms.zdv.uni-mainz.de/startseite/wp-content/plugins/jgu-tools/dist/styles/frontend.css?ver=1642780034' type='text/css' media='all' />
<link rel='stylesheet' id='jgu-study-finder_frontend.css-css' href='https://www.uni-mainz.de/wp-content/plugins/jgu-study-finder/dist/frontend.css?ver=1645633275' type='text/css' media='all' />
<link rel='stylesheet' id='wpml-legacy-horizontal-list-0-css' href='https://cms.zdv.uni-mainz.de/startseite/wp-content/plugins/sitepress-multilingual-cms/templates/language-switchers/legacy-list-horizontal/style.min.css?ver=1' type='text/css' media='all' />
<style id='wpml-legacy-horizontal-list-0-inline-css' type='text/css'>
.wpml-ls-statics-footer a, .wpml-ls-statics-footer .wpml-ls-sub-menu a, .wpml-ls-statics-footer .wpml-ls-sub-menu a:link, .wpml-ls-statics-footer li:not(.wpml-ls-current-language) .wpml-ls-link, .wpml-ls-statics-footer li:not(.wpml-ls-current-language) .wpml-ls-link:link {color:#444444;background-color:#ffffff;}.wpml-ls-statics-footer .wpml-ls-sub-menu a:hover,.wpml-ls-statics-footer .wpml-ls-sub-menu a:focus, .wpml-ls-statics-footer .wpml-ls-sub-menu a:link:hover, .wpml-ls-statics-footer .wpml-ls-sub-menu a:link:focus {color:#000000;background-color:#eeeeee;}.wpml-ls-statics-footer .wpml-ls-current-language > a {color:#444444;background-color:#ffffff;}.wpml-ls-statics-footer .wpml-ls-current-language:hover>a, .wpml-ls-statics-footer .wpml-ls-current-language>a:focus {color:#000000;background-color:#eeeeee;}
/*# sourceURL=wpml-legacy-horizontal-list-0-inline-css */
</style>
<style id='wp-block-heading-inline-css' type='text/css'>
h1:where(.wp-block-heading).has-background,h2:where(.wp-block-heading).has-background,h3:where(.wp-block-heading).has-background,h4:where(.wp-block-heading).has-background,h5:where(.wp-block-heading).has-background,h6:where(.wp-block-heading).has-background{padding:1.25em 2.375em}h1.has-text-align-left[style*=writing-mode]:where([style*=vertical-lr]),h1.has-text-align-right[style*=writing-mode]:where([style*=vertical-rl]),h2.has-text-align-left[style*=writing-mode]:where([style*=vertical-lr]),h2.has-text-align-right[style*=writing-mode]:where([style*=vertical-rl]),h3.has-text-align-left[style*=writing-mode]:where([style*=vertical-lr]),h3.has-text-align-right[style*=writing-mode]:where([style*=vertical-rl]),h4.has-text-align-left[style*=writing-mode]:where([style*=vertical-lr]),h4.has-text-align-right[style*=writing-mode]:where([style*=vertical-rl]),h5.has-text-align-left[style*=writing-mode]:where([style*=vertical-lr]),h5.has-text-align-right[style*=writing-mode]:where([style*=vertical-rl]),h6.has-text-align-left[style*=writing-mode]:where([style*=vertical-lr]),h6.has-text-align-right[style*=writing-mode]:where([style*=vertical-rl]){rotate:180deg}
/*# sourceURL=https://www.uni-mainz.de/wp-includes/blocks/heading/style.min.css */
</style>
<style id='wp-block-paragraph-inline-css' type='text/css'>
.is-small-text{font-size:.875em}.is-regular-text{font-size:1em}.is-large-text{font-size:2.25em}.is-larger-text{font-size:3em}.has-drop-cap:not(:focus):first-letter{float:left;font-size:8.4em;font-style:normal;font-weight:100;line-height:.68;margin:.05em .1em 0 0;text-transform:uppercase}body.rtl .has-drop-cap:not(:focus):first-letter{float:none;margin-left:.1em}p.has-drop-cap.has-background{overflow:hidden}:root :where(p.has-background){padding:1.25em 2.375em}:where(p.has-text-color:not(.has-link-color)) a{color:inherit}p.has-text-align-left[style*="writing-mode:vertical-lr"],p.has-text-align-right[style*="writing-mode:vertical-rl"]{rotate:180deg}
/*# sourceURL=https://www.uni-mainz.de/wp-includes/blocks/paragraph/style.min.css */
</style>
<style id='wp-block-button-inline-css' type='text/css'>
.wp-block-button__link{align-content:center;box-sizing:border-box;cursor:pointer;display:inline-block;height:100%;text-align:center;word-break:break-word}.wp-block-button__link.aligncenter{text-align:center}.wp-block-button__link.alignright{text-align:right}:where(.wp-block-button__link){border-radius:9999px;box-shadow:none;padding:calc(.667em + 2px) calc(1.333em + 2px);text-decoration:none}.wp-block-button[style*=text-decoration] .wp-block-button__link{text-decoration:inherit}.wp-block-buttons>.wp-block-button.has-custom-width{max-width:none}.wp-block-buttons>.wp-block-button.has-custom-width .wp-block-button__link{width:100%}.wp-block-buttons>.wp-block-button.has-custom-font-size .wp-block-button__link{font-size:inherit}.wp-block-buttons>.wp-block-button.wp-block-button__width-25{width:calc(25% - var(--wp--style--block-gap, .5em)*.75)}.wp-block-buttons>.wp-block-button.wp-block-button__width-50{width:calc(50% - var(--wp--style--block-gap, .5em)*.5)}.wp-block-buttons>.wp-block-button.wp-block-button__width-75{width:calc(75% - var(--wp--style--block-gap, .5em)*.25)}.wp-block-buttons>.wp-block-button.wp-block-button__width-100{flex-basis:100%;width:100%}.wp-block-buttons.is-vertical>.wp-block-button.wp-block-button__width-25{width:25%}.wp-block-buttons.is-vertical>.wp-block-button.wp-block-button__width-50{width:50%}.wp-block-buttons.is-vertical>.wp-block-button.wp-block-button__width-75{width:75%}.wp-block-button.is-style-squared,.wp-block-button__link.wp-block-button.is-style-squared{border-radius:0}.wp-block-button.no-border-radius,.wp-block-button__link.no-border-radius{border-radius:0!important}:root :where(.wp-block-button .wp-block-button__link.is-style-outline),:root :where(.wp-block-button.is-style-outline>.wp-block-button__link){border:2px solid;padding:.667em 1.333em}:root :where(.wp-block-button .wp-block-button__link.is-style-outline:not(.has-text-color)),:root :where(.wp-block-button.is-style-outline>.wp-block-button__link:not(.has-text-color)){color:currentColor}:root :where(.wp-block-button .wp-block-button__link.is-style-outline:not(.has-background)),:root :where(.wp-block-button.is-style-outline>.wp-block-button__link:not(.has-background)){background-color:initial;background-image:none}
/*# sourceURL=https://www.uni-mainz.de/wp-includes/blocks/button/style.min.css */
</style>
<style id='wp-block-columns-inline-css' type='text/css'>
.wp-block-columns{box-sizing:border-box;display:flex;flex-wrap:wrap!important}@media (min-width:782px){.wp-block-columns{flex-wrap:nowrap!important}}.wp-block-columns{align-items:normal!important}.wp-block-columns.are-vertically-aligned-top{align-items:flex-start}.wp-block-columns.are-vertically-aligned-center{align-items:center}.wp-block-columns.are-vertically-aligned-bottom{align-items:flex-end}@media (max-width:781px){.wp-block-columns:not(.is-not-stacked-on-mobile)>.wp-block-column{flex-basis:100%!important}}@media (min-width:782px){.wp-block-columns:not(.is-not-stacked-on-mobile)>.wp-block-column{flex-basis:0;flex-grow:1}.wp-block-columns:not(.is-not-stacked-on-mobile)>.wp-block-column[style*=flex-basis]{flex-grow:0}}.wp-block-columns.is-not-stacked-on-mobile{flex-wrap:nowrap!important}.wp-block-columns.is-not-stacked-on-mobile>.wp-block-column{flex-basis:0;flex-grow:1}.wp-block-columns.i
sitemap.xml 200 OK
Type URL Set URLs 0 entries Valid XML No
C
URL Variants
Action
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
Warning::
HTTP→HTTPS redirect uses 302 instead of 301
Got: 302 temporary redirect Expected: 301 permanent redirect

www / non-www

200https://www.uni-mainz.de/
200https://uni-mainz.de/

Inconsistent — duplicate content risk

HTTP → HTTPS

308http://uni-mainz.de/ → https://uni-mainz.de/

Use 301 (permanent) instead of 302 (temporary)

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

Certificate validity

75
days left
0d 30d 60d 90d+

Recommended actions

  • Enable HSTS: Strict-Transport-Security: max-age=31536000; includeSubDomains
  • 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, 53 ms lookup
PASS
1 A records, 53 ms lookup
Info::
Resolves to 1 IPv4 address(es)
Got: 134.93.178.31
Info::
Single A record — no DNS redundancy
Multiple A records provide failover if one server goes down.
Info::
Has 1 IPv6 (AAAA) record(s)
Got: 2001:4c80:40:63c:4:86ff:fe5d:b21f
Info::
2 nameserver(s) configured
Got: xlink1.xlink.net, ns-extern.zdv.uni-mainz.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
Info::
DNS resolution time: 53 ms
Got: 53 ms
A134.93.178.31
AAAA2001:4c80:40:63c:4:86ff:fe5d:b21f
CNAME—
NSxlink1.xlink.net, ns-extern.zdv.uni-mainz.de
MX
100 mailgate-3.zdv.uni-mainz.de
100 mailgate-2.zdv.uni-mainz.de
100 mailgate-1.zdv.uni-mainz.de
TXT
SPF v=spf1 mx ip4:134.93.178.240/28 ip6:2001:4c80:40:62d::/64 ~all
v=spf2.0/mfrom,pra mx ip4:134.93.178.240/28 ip6:2001:4c80:40:62d::/64 ~all
canva-site-verification=AMtvtZhvPy37QDJDMcz3yA
CAALookup not available with standard resolver
Resolved in 53 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.

A
Redirect Chain
1 redirect(s), 950 ms total
PASS
1 redirect(s), 950 ms total
Info::
Single redirect
Got: https://uni-mainz.de → https://www.uni-mainz.de (302)
Info::
WWW normalization redirect
Info::
Uses 302 (temporary) redirect
If permanent, use 301 instead.
Got: https://uni-mainz.de
Info::
Redirect overhead: 950 ms total
Got: 950 ms

https://uni-mainz.de

82 ms · HTTP/1.1

302

https://www.uni-mainz.de

868 ms · HTTP/1.1 FINAL

#URLStatusTimeProtocolServer
1https://uni-mainz.de30282 msHTTP/1.1Caddy
2https://www.uni-mainz.de200868 msHTTP/1.1Apache

See the visual redirect chain in the HTTP Probe tab →

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

A+
IPv6 Readiness
IPv6 reachable (26 ms)
PASS
IPv6 reachable (26 ms)
Info::
IPv6 is configured and reachable at 2001:4c80:40:63c:4:86ff:fe5d:b21f
Got: 26 ms connect
IPv6 Ready
AAAA Records 2001:4c80:40:63c:4:86ff:fe5d:b21f Connection Reachable (26 ms)
A+
Domain Intelligence
uni-mainz.de
PASS
uni-mainz.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.
Domain expiry

Unknown

SSL certificate

75 days

Issued by Let's Encrypt

Domain age

Unknown

DNSSEC

Status unknown

Protects against DNS spoofing

Hosting

Unknown

2001:4c80:40:63c:4:86ff:fe5d:b21f

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 2001:4c80:40:63c:4:86ff:fe5d:b21f
Data source: whois (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 128 ms — DNS, TCP, TLS, TTFB, content transfer breakdown
PASS
DNS Lookup DNS Lookup — time to resolve the domain name to an IP address.
48 ms
TCP Connect TCP Connect — time to establish a TCP connection to the server.
26 ms
TLS Handshake TLS Handshake — time to complete the HTTPS encryption handshake.
28 ms
Time to First Byte Time to First Byte — how long the server takes to respond with the first byte of data.
128 ms
Total Time Total request time from DNS lookup through full response.
128 ms

Connection waterfall

DNS Lookup 48 ms TCP Connect 26 ms TLS Handshake 28 ms Server Processing 26 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.

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