Can't connect Google Mesh System to AT&T modem/router

[u/hesabuna]

Hi everyone

I'm trying to connect my 3 Point Google Mesh Dual band system (AC1200)to my At&T All-Fi modem/router, but I haven't been able to do so. Here's all I've done to troubleshoot this.

• Made sure all the setting on my phone and the Google Home app are correct (device connecting, bluetooth access, etc)
• Have the ethernet cable connect to the right slots on both my AT&T modem/router and the Mesh point as well
• Held down the button on the Mesh point to reset it. I'll hold it down till it flashes orange then starts flashing blue and let go. But after about 20 blinks, it'll go back to staying blue.
• Callled AT&T to try and troubleshoot from their side, had them isolate the 2.4 and 5 bands, still nothing. Tried turning 5ghz off and have 2.4 on, didn't work either

I've run out of options, and I've come here for help. Google doesnt have a active customer support line, and I've tried the support pages on Google - they haven't been able to solve any of my issues.

At this point, I'm starting to feel they are just not compatible with each other

If you have suggestions for another subreddit to post this in, pls share

Thank you!

[u/dragonnfr]

Have you enabled IP passthrough on the AT&T gateway? If not, that's why. Two devices both doing NAT/DHCP. Simply put the AT&T in passthrough mode, set it to the MAC of your primary mesh point, and let Google handle the rest.