gdz.ru

Readiness by lane

Green: gdz.ru. Thin bar: Education & Online Learning peer median.

Priority fixes for gdz.ru

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.

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

   34% of Education & Online Learning 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.

   On Cloudflare: Use Cache Rules to set edge and browser TTLs for static file paths.

   45% of Education & Online Learning peers do this.

   Guide: Browser Caching Guide for Website Owners

3. Priority 3 · Harden

   DMARC policy enforces quarantine or reject

   Observed: No DMARC record was found at _dmarc.gdz.ru.

   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.

   36% of Education & Online Learning peers do this.

   Guide: A Practical Website Health Check for Owners

4. Priority 4 · Accelerate

   Modern image formats in use

   Observed: The homepage had 71 images and none used WebP or AVIF.

   What to do: Serve WebP or AVIF with a JPEG or PNG fallback, either through an image CDN or by generating both formats at build time.

   On Cloudflare: Cloudflare Polish can convert images to WebP.

   32% of Education & Online Learning peers do this.

   Guide: AVIF, WebP, JPEG, and PNG: Choose the Right Image Format

What gdz.ru already does well

Practices fewer than half of Education & Online Learning peers use.

• Structured data presentJSON-LD structured data found.41% of peers
• No render-blocking scripts in <head>Head scripts load without blocking.42% of peers

What we saw

Homepage checked

https://gdz.ru/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Let's Encrypt, 89-day validity, expiring 2026-11-12

DNS operators

Cloudflare

Homepage HTML

315 KB, gzip

Images on homepage

71 (jpg 58, svg 9, png 3)

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

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Education & Online Learning readiness benchmark