Firefox ESR 153.4.0esr — the first minute without a single click
How we tested: Debian 13, fresh profile, headless mode, 60 seconds, nothing clicked. 15.10.2026. We repeated the run — the result matched. Every network request was recorded; the code was not decompiled.
What is built in. Mozilla’s own telemetry (Glean). The Google Analytics and Facebook code inside Firefox are stubs the browser substitutes for blocked trackers. The Hotjar address comes from the rules Firefox uses to reject cookie banners on its own.
Where it connected — 31 server names:
| Who | Servers | Why |
|---|---|---|
| Mozilla: settings and lists | firefox.settings.services.mozilla.com, firefox-settings-attachments.cdn.mozilla.net, content-signature-2.cdn.mozilla.net | remote settings, blocklists, signature checks |
| Mozilla: telemetry | incoming.telemetry.mozilla.org | usage statistics — within the first 5 seconds |
| Mozilla: experiments | normandy.cdn.mozilla.net | “studies” and gradual feature rollouts |
| Mozilla: region | location.services.mozilla.com, classify-client.services.mozilla.com | country detection by IP |
| Mozilla: advertising | ads.mozilla.org, ads-img.mozilla.org | sponsored new-tab tiles, 6–7 image downloads |
| Mozilla: other | aus5.mozilla.org, push.services.mozilla.com, services.addons.mozilla.org, accounts.firefox.com, www.mozilla.org, detectportal.firefox.com | updates, push notifications, add-ons, account, network check |
| Anonymising relay | prod.ohttp-gateway.prod.webservices.mozgcp.net, mozilla-ohttp.fastly-edge.com | OHTTP: some data goes through a relay that hides the IP from Mozilla |
safebrowsing.googleapis.com, update.googleapis.com, edgedl.me.gvt1.com | dangerous-site checks (Safe Browsing), download of a Google component | |
| DNS lookup only, no connection | www.amazon.de, www.adidas.ch, temuaffiliateprogram.pxf.io, www.youtube.com, www.reddit.com, www.wikipedia.org | new-tab tile addresses, including sponsored ones and a Temu affiliate link: the browser looks up their addresses in advance |
| Service checks | cloudflare-dns.com, ipv4only.arpa, example.org | DNS-over-HTTPS and network checks |
A DNS lookup is not a connection, but your provider and the DNS server see it. The set of sponsored tiles depends on the region Firefox detects from the IP.
In Firefox’s favour: it blocks trackers (stubs instead of their code), rejects cookie banners on its own and sends some data through an OHTTP relay that hides the user’s IP.
How to turn it off. In Settings: “Privacy & Security” → “Firefox Data Collection and Use”, and “Home” → new tab content. Or in about:config:
| What | Setting → value |
|---|---|
| Telemetry | datareporting.healthreport.uploadEnabled → false |
| “Studies” | app.shield.optoutstudies.enabled → false |
| Sponsored shortcuts | browser.newtabpage.activity-stream.showSponsoredTopSites → false |
| Sponsored stories | browser.newtabpage.activity-stream.showSponsored → false |