HardwareNov 12, 2026, 12:34 AM UTC·1 min read

Fritzbox 5690 Pro Gets FritzOS 8.51 With DNS Ad Blocker

FritzOS 8.51 is available for the Fritzbox 5690 Pro and adds an ad blocker based on a DNS blocklist. Newer hardware revisions ship with less RAM and flash.

A Fritzbox 5690 Pro router on a desk with its status LEDs lit. — Image: c't Magazin

Firmware 8.51 is now available for the Fritzbox 5690 Pro. The headline addition of FritzOS 8.51 is an ad blocker that works through a DNS blocklist, filtering unwanted domains at the router level.

Less memory in new revisions

The update comes with a catch for buyers: newer hardware revisions of the Fritzbox 5690 Pro are equipped with less RAM and less flash storage than earlier units. Which devices are affected, and by how much, is not detailed in the information available so far.

Why it matters

A DNS-based blocker applies to every device on the home network without software on each device. At the same time, the reduced memory is a reminder to check the hardware revision before buying, especially for those planning to use extra router functions.

Apps worth a look

SUMO: the number puzzle

Tap the right tiles, add them up, hit the target. Easy to learn, hard to master. Free, for all ages.

Dialo: learn languages by speaking

Talk to an AI conversation partner; every sentence comes back corrected and explained in your language. 9 languages, A1 to C2.

ediviewer: read EDI files like documents

Open EDIFACT and X12 messages, see every segment explained, convert to JSON/XML, export PDF and Excel. Runs locally, no upload.

giftdetect: the right gift in minutes

Pick who it is for, the occasion and their personality. The search engine reads product descriptions from local shops and ranks what fits. Free, no sign-up.

Tags:fritzboxfritzosavmrouteradblockerfirmware