Just a quick update on this. I tried a few things that were suggested on other posting. I have switched the main P9 with one of the others. And also reset the Comcast modem/router. I will see how things pan out over the next few hours. 

@deatiit86 did it make any difference? I have the same issues and it appears a lot of people do. My ISP router can't be put in bridge mode so have to use access point mode on the Deco but I still get the lose of access to internet. Like you said can be hours with no problems and then every 5-15 minutes. 

@deatiit86 

I run the Deco M9 in AP mode, but it sounds like it could be a dns / routing issue.

Also, are you saying you are running your gateway in Bridge mode?

Dumb Cable <-> Comcast (Bridge mode?) <-> P9 Master (Internet connection = fixed + DHCP + DNS server) ~~~ P9 Slave

I would say you should have...

Dumb Cable <-> Comcast (DHCP + DNS server) <-> P9 Master (DHCP subnet? server) ~~~ P9 Slave

or..

Dumb Cable <-> Comcast (Bridge) <-> P9 Master (Internet connection = dynamic + DHCP subnet? server) ~~~ P9 Slave

What is xfinity?

As I mentioned, I have mine set to AP mode, therefore routing + IP address are handled by my router connected to the outside world.

As far as I can tell, the Deco system needs a valid tie to the real "gateway" as it seems to use a secondary DHCP server system, under which the main unit acts as a gateway. it does this to allow for the multi channel fallover sytem to ensure a good experience for all users;

Outside World <-> Comcast (Handles DNS & Local IP tablel via DHCP) <-> P9 Master (with Local IP + sub DHCP server) ~~~ P9 Slave + Devices (with sub IP table + sub DNS from P9 Master)

So without a "real" gateway, and the P9 set on fixed internet the Deco doesn't know where to go, it can't talk to the Dumb Cable to get the relevant settings. Hence, your local network is okay, but the WWW is blocked (it can't route). If you are running the main (comcast) router in bridge mode, make sure to set the P9 internet connection type to "dynamic".

Does that make sense?

Also, I remember years ago pulling my hair out over a router that didn't serve internet properly to Lan / Wan 1, ignoring Lan 1 and plugging into Lan 2 and all was ok...

@Scoredo yes, it seems to be stable now. My internet connection has been up been up for 2 days.

@CasaP Xfinity is another name for my cable provider (Comcast). And, yes, my topology is:

Dumb Cable <-> Comcast (Bridge) <-> P9 Master (Internet connection = dynamic + DHCP subnet? server) ~~~ P9 Slave

So here is what I did.

1. Reset all Deco P9's (3 of them) to factory default and powered them down

2. Deleted network for the Deco app on my phone

3. Turned off my Cable modem/router

4. Wired the Deco P9 to the modem/router and then turned the modem/router and Deco P9 back on.  

5. Set everything up again. 

This seemed to reset everthing and configure them completely and correctly. 

@deatiit86

@deatiit86 

Glad to hear yu got it sorted.

Same issue as everyone else here has reported - frequent and random internet connection dropouts.

My Deco P9 is connected via ethernet to a DrayTek Vigor 130 ADSL2+/VDSL Modem.

I'm running the latest official firmware (Deco_P9(EU)_V1_200513).

Tried logging on via a web browser by typing in my IP address and was shocked at how pathetic the configuration options are. You can't even set the wifi channel!

Not sure if my issues are related to my Decos trying to connect via wifi instead of powerline backhaul, as I seem to get issues even when I am next to my main Deco (which is plugged directly into my modem), but it would be nice to be able to toggle a "force powerline backhaul" setting via the app or via the web interface.

Not sure how much longer I can stick this product - may have to see if I can return it to Amazon as it is really poor - a shame because I sold off my old TP-Link powerline adapters and BT Whole Home Mesh Wifi Discs to "upgrade" to the P9... as it is it looks like it's going to cost me even more money to replace this system with something half decent.

TP-Link need to pull their finger out and sort this firmware out ASAP.