o2online.de

Readiness by lane

Green: o2online.de. Thin bar: Telecommunications & Internet peer median.

Priority fixes for o2online.de

Ordered by impact and by how common each practice is among peers.

1. Priority 1 · Harden

   HSTS kept for at least a year

   Observed: Strict-Transport-Security was sent with a max-age of 180 days, below the one-year benchmark.

   Why it matters: HSTS tells browsers to use HTTPS for your host on every later visit, which removes the window where a first HTTP request can be intercepted.

   What to do: Send Strict-Transport-Security on HTTPS responses. Start with a short max-age (for example 300 seconds), confirm every subdomain works over HTTPS, then raise it in steps to 31536000. Add includeSubDomains only when all subdomains are HTTPS. HSTS preload is optional and hard to undo; hstspreload.org itself does not recommend it by default.

   On Cloudflare: Enable HSTS under SSL/TLS > Edge Certificates > HTTP Strict Transport Security and raise max-age gradually.

   54% of Telecommunications & Internet peers do this. Limit: Read from the homepage response only; other pages or regions may send different headers.

   Guide: HTTPS and TLS Guide for Website Owners

2. Priority 2 · Harden

   DMARC policy enforces quarantine or reject

   Observed: The DMARC policy for o2online.de was p=none, which asks receivers to take no action on failing mail.

   What to do: Publish DMARC with p=none and a reporting address first, fix any legitimate senders that fail SPF or DKIM alignment, then move to quarantine and finally reject.

   59% of Telecommunications & Internet peers do this.

   Guide: A Practical Website Health Check for Owners

3. Priority 3 · Accelerate

   No render-blocking scripts in <head>

   Observed: The homepage <head> loaded 1 external script without async or defer.

   What to do: Add defer to scripts that need the DOM, async to independent ones such as analytics, or move them to the end of the body.

   37% of Telecommunications & Internet peers do this.

   Guide: Control Third-Party Scripts Before They Control Your Page

4. Priority 4 · Harden

   CAA records limit who can issue certificates

   Observed: No CAA record was found for o2online.de, so any public certificate authority may issue for it.

   What to do: Publish CAA records naming every CA you actually use, including the CAs your CDN uses for managed certificates. Add an iodef contact if you want reports.

   On Cloudflare: Cloudflare documents which CAs its managed certificates need; include them in your CAA records.

   15% of Telecommunications & Internet peers do this.

   Guide: HTTPS and TLS Guide for Website Owners

What o2online.de already does well

Practices fewer than half of Telecommunications & Internet peers use.

• Certificate lifetime of 100 days or lessShort-lived 90-day certificate from Google Trust Services, already inside the 2027 limit.28% of peers
• Reachable over IPv6IPv6 address published.33% of peers
• Content Security Policy presentContent-Security-Policy present.48% of peers

What we saw

Homepage checked

https://www.o2online.de/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Google Trust Services, 90-day validity, expiring 2026-12-11

CDN or edge

Cloudflare

DNS operators

1 self-run or other nameserver domain

HSTS

max-age 180 days

DMARC policy

p=none

Homepage HTML

225 KB, br

Images on homepage

54 (webp 131, png 39, jpg 38)

Limits: homepage only, one location, one moment. Header checks reflect the homepage response; other pages may differ.

Stack and providers

Seen in the homepage response, certificate and DNS. Provider pages compare how their customers configure the same checks.

All 31 checks

Select a gap for the method and fix. How each check works

Compare with other Telecommunications & Internet sites

• bell.ca74
• claro.com.ar74
• myvi.in74
• niointernet.com.br73
• three.co.uk74

Telecommunications & Internet readiness benchmark