This is just a post to help anyone who may have a similar issue in the future.

I recently decided to upgrade my Snap ADSL connection to VDSL. Accordingly, I received a new Fritz!box 7490 VDSL modem/router to replace my existing Netgear unit. I use Netflix via Unotelly DNS proxy.

Once I had it all set up and working (changing DHCP to the right range, reconfiguring WLAN etc) I noticed that Netflix (although accessible) would not play any content, rather would pause at 25% loading then error out (across all clients including PC). Vudu (another online streaming service) however still worked fine.

I experimented with cutting out Unotelly (ie falling back to local NZ Netflix direct) and blackholing Google DNS (static route to an unused address on the local LAN). No change.

Was thinking I'd have to revert to my previous router when I eventually noticed entries in the Fritzbox log saying sessions direct to specific IP addresses had been blocked. Turns out that (by default?) the Fritzbox has a basic level of filtering applied which blocks direct access by IP address (as opposed to URL).

Simple fix was to change the Fritzbox profile for the specific streaming devices/clients to enable true 'Unrestricted' rather than 'Standard' access.

Full disclosure - I'm not 100% sure that the direct access by IP address was blocked out of the box, or if I enabled it somehow during setup :-) In which case, my bad, sorry Snap!

Hopefully this helps someone in future googling the issue. Personally now waiting for Chorus to turn on VDSL...