century21.fr

Readiness by lane

Green: century21.fr. Thin bar: Real Estate & Property Listings peer median.

Priority fixes for century21.fr

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

1. Priority 1 · Harden

   HSTS kept for at least a year

   Observed: The homepage response did not include a Strict-Transport-Security header.

   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.

   43% of Real Estate & Property Listings 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 · Accelerate

   Static files cached for 30 days or more

   Observed: A same-site stylesheet or script was cacheable for no max-age, short of the 30-day benchmark.

   What to do: Give versioned (fingerprinted) CSS, JavaScript, fonts and images Cache-Control: public, max-age=31536000, immutable, and change the file name whenever the content changes.

   51% of Real Estate & Property Listings peers do this.

   Guide: Browser Caching Guide for Website Owners

3. Priority 3 · Harden

   DMARC policy enforces quarantine or reject

   Observed: The DMARC policy for century21.fr 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.

   51% of Real Estate & Property Listings peers do this.

   Guide: A Practical Website Health Check for Owners

4. Priority 4 · Enable

   Canonical URL declared

   Observed: The homepage did not declare a canonical URL.

   What to do: Add a self-referencing canonical link to every indexable page, using the final https:// URL.

   77% of Real Estate & Property Listings peers do this.

   Guide: Canonical Tags: A Decision Guide for Duplicate URLs

What century21.fr already does well

Practices fewer than half of Real Estate & Property Listings peers use.

• Nameservers spread across providersNameservers spread across more than one operator.7.5% of peers
• No render-blocking scripts in <head>Head scripts load without blocking.49% of peers

What we saw

Homepage checked

https://www.century21.fr/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

DigiCert, 392-day validity, expiring 2027-03-15

DNS operators

4 self-run or other nameserver domains

DMARC policy

p=none

Homepage HTML

130 KB, gzip

Images on homepage

9 (jpg 18, webp 11, png 4)

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 Real Estate & Property Listings sites

• dotloop.com60
• entree.nu60
• nestoria.fr61
• nestoria.it61
• streeteasy.com61

Real Estate & Property Listings readiness benchmark