jazztel.com

Readiness by lane

Green: jazztel.com. Thin bar: Telecommunications & Internet peer median.

Priority fixes for jazztel.com

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 Next.js: Add the header in the headers() option of next.config.js for all routes.

   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 jazztel.com 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 · Enable

   Social preview image set

   Observed: The homepage had no og:image, so shared links may show without a preview image.

   What to do: Add Open Graph tags, including og:image with a 1200 x 630 image.

   59% of Telecommunications & Internet peers do this.

   Guide: SEO Checklist for a New Website

4. Priority 4 · Harden

   CAA records limit who can issue certificates

   Observed: No CAA record was found for jazztel.com, 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.

   15% of Telecommunications & Internet peers do this.

   Guide: HTTPS and TLS Guide for Website Owners

What jazztel.com already does well

Practices fewer than half of Telecommunications & Internet peers use.

• HTTP/3 advertisedHTTP/3 advertised.13% of peers
• Certificate lifetime of 100 days or lessShort-lived 90-day certificate from Google Trust Services, already inside the 2027 limit.28% of peers
• No render-blocking scripts in <head>Head scripts load without blocking.37% of peers

What we saw

Homepage checked

https://www.jazztel.com/

Homepage response

HTTP 200

TLS

TLSv1.3, HTTP/2

Certificate

Google Trust Services, 90-day validity, expiring 2026-11-28

CDN or edge

Google edge

Platform or framework

Next.js

DNS operators

1 self-run or other nameserver domain

HSTS

max-age 180 days, includeSubDomains

DMARC policy

p=none

Homepage HTML

1,215 KB, gzip

Images on homepage

9 (svg 18, webp 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

Compare with other Telecommunications & Internet sites

• au.com76
• claro.com.gt77
• fizz.ca77
• telekom.si77
• windtre.it79

Telecommunications & Internet readiness benchmark