No access to internal IP via wifi, ethernet fine

Folks, looking for some help. If I had any hair I'd be pulling it out, ha.

I have moved over to Sky FTTC, was previously on their unlimited ADSL2+ service using a Billion 7800n.
With FTTC they have seen fit to force MER authentication, so until that is cracked I'm forced to use their sagecom [email protected] 2504N with their modified fibre firmware, which is horrid!

I have all of my DHCP address reservations and port forwarding sorted (that was a mare too)

I have a Qnap NAS in the house which 3 mac's use to backup to wirelessly via time machine.
Up until implementing the sky router, everything was grand.
Now I can only occasionally access the NAS, whether it be via it's GUI, Finder, Time Machine, Ping or whatever.
There's no rhythm to it, sometimes one machine can access and another can't. All at different times of the day.
It's also stopping me accessing the GUI of my HG612, actually anything on the network.

BUT, if I plug an ethernet cable in, everything is fine once again!
Also devices upstairs connected to my access point are fine, I'm guessing this is because the Sky router sees them as cabled.

Any advise on why this may be?

Is there a "wireless isolation" setting on the router?

Is there a DMZ setting on the router?

Yes, it has both but nothing is in the DMZ and I have wireless isolation unticked.

EDIT 1:
Ticking wireless isolation has just resolved it!
Maybe they've reversed (read: cocked up) the check box on the GUI?

I also forgot to mention that remote access to my NAS has not played up at all.

EDIT 2:
It only worked for a matter of seconds, back to no access now.

Edited by Mot (Fri 23-Mar-12 13:42:48)

Sounds like a cock-up. Ok, put a proper router in the DMZ and use that...

Post deleted by RobertoS

Or add a second wireless access point. (I'm assuming he doesn't want to add load to the existing one).

Maybe it will now work correctly if you untick it.

Have you tried a factory reset?

Further to my reply to BatBoy, could you use your previous router as the second access point?

I'd like to be able to completely get rid of the Sly router but that's not possible yet so I'm going to try and add a WNDR3700 and use the Sly router as just a modem if I can.

The Sly router is very underpowered IMO, I'd like to take as much load off it as I can. The access point upstairs is too far away to completely cover the house too.

It's not going to be pretty, 3 devices coming from once socket in the living room.