R8500 fails to connect

[roger567]

For some months now, the router fails to connect to websites and displays messages like "Hmmm… can't reach this page  www.website.com took too long to respond".

Usually if I click refresh the website appears, but this happens on all websites, including those like google.com and bbc.co.uk that are quite fast to respond.

This happens on multiple computers (all Windows) on the network.

If I reboot the router, websites load normally for some hours or a day or so, but I have taken to rebooting daily at least.

I have tried

1. a range of different DNS addresses, including those from my ISP, from Google like 8.8.8.8. That doesn't seem to make a difference.

2. changing the Internet connection setting (currently 6to4 Tunnel)

3. reinstalling the router firmware

4. fixed IP and DHCP addresses

My ISP says it is nothing to do with them (predictably), but friends on the same ISP and using the same DNS servers are not having this problem.

Most features like QoS and NAT filtering are disabled.

The only thing I have found that affects it is rebooting the router.

Any idea what else I can try?

Thanks

[plemans]

What modem/gateway is it connected to?

[roger567]

The R8500 connects via ethernet to the ISP's router (called a Centro Business 2), which is in PPPoE passthrough mode.

The ISP's router connects directly to the fibre optic cable that goes to the outside world.

The R8500 handles the internet connection (user ID, password etc.).

[plemans]

the centro might be in passthrough mode but I've seen that mode not function properly before. 

have you tried running it in router mode and putting the R8500 in access point mode? 

[roger567]

Thanks, I will switch it over and try it for a few hours to see if it is different.

It has been in PPPoE mode for some years without problems and the problem started some months ago.

Presumably I can keep the R8500 as DHCP server and have the Centro doing as little as possible.

[plemans]

If you have the centra in router mode and the R8500 with dhcp,  you're still in a double nat. 

[roger567]

Switching the Centro to router mode gave very similar results.

Replacing the R8500 with an R7500 and putting the Centro back to PPPoE seems to work well.

Still it is early days, I will try running the R7500 for as long as they let me keep it to see if it just got lucky, or whether it really is different.

[roger567]

I had to give the other router back (it was an R7000 not 7500 as I wrote before).

Shame - it worked perfectly.

Is there any way to roll back firmware updates and go back to a version from several months ago before this started?

What else could I try?

[plemans]

Yes, you can roll back firmware. 

you go to the support site for your device and click on downloads. then its under "view previous versions"

Download the older verison and extract it. then just follow the manual firmware update process from the manual but use the older firmware you downloaded. I'd recommend doing this over a hardwired connection, factory reset after the change, and do a clean install (not from backup)

https://www.netgear.com/support/product/R8500.aspx

[roger567]

Thanks Plemans,

In the meantime, I have heard that I can have the R7000 back and keep it, so I will give up on the R8500.