jhollington Thank you so much, truly appreciate it!  When I think about it, I did try prior to installing the firmware update.  I will give it a try tonight

jhollington I was able to get it to work right away.  That said, I had to unplug the gateway to move it and I just can't get it to connect anymore.  It either won't give up the internal private IP or won't connect to internet if it sees the public one.  Unfortunately, it seems to be impacting my wireless speedtests.  Have you had any issues since? Thanks

Oully I've had the same problem... It's very persnickety if you try to reconnect it, or even sometimes if it reboots after a software update, and it's hard to figure out what's going on exactly... it seems that once it's "offline" it's impossible to actually manage it from the app, even when you're connected directly to its Wi-Fi. I can't reboot it when it's offline, and in fact I can't even change it to use a static IP, as it refuses to save any settings at all — it's like the app is showing the last known settings but not actually communicating with the Eero, so it's extremely frustrating. 

I think this may be why it still seems to be showing the old IP address, simply because the Eero app isn't actually reading the new settings — I rebooted my Bell Home Hub, and of course it got a new public IP, and according to its DHCP settings, it's even assigned it to the Eero, but the Eero refuses to connect to the Internet, and the app still shows the old static IP address, so it's hard to tell whether it's the app not showing the new settings or the Eero not actually updating itself with the new DHCP-assigned IP address that the HH3000 handed out. My guess is that it's the first scenario, since I can't save any changes to the configuration either — It seems as though the Eero app doesn't actually want to communicate directly with the Eero over Wi-Fi, but rather expects to work through Eero's cloud servers, so when Eero isn't connected, the app can't actually communicate with it properly. 

In the end, going through the following steps seems to fix it whenever this does happen:

1. On the Home Hub 3000, disable Advanced DMZ (you can leave the DMZ on, but uncheck the "Advanced DMZ" on the bottom. Be sure to click "Save" to confirm the change.
2. Soft Reset the Eero Gateway by pressing the reset button until the LED turns yellow and then releasing it.
3. When the Eero Gateway comes back, in should get an internal IP on whatever subnet the HH3K is configured to use.
4. Re-enable "Advanced DMZ" on the HH3K.
5. Reboot the HH3K (under Advanced->Resets->Restart)
6. Soft Reset the Eero Gateway again (hold reset until LED turns yellow and release)

In some cases, simply toggling advanced DMZ off and back on and then soft resetting the Eero makes it come back okay, but not always. The soft reset seems to force the Eero to pick up a new IP address, but it may need to pick up a different one (e.g. step #3) before it can come back to the original public IP. 

It's a convoluted process, and I have no idea why the Eero needs to go through this, but there's obviously an incompatibility with how the HH3K implements Advanced DMZ and what the Eero gateway wants to see. It's definitely a problem Eero needs to solve, however, as I've used at least five other routers from different brands with the Advanced DMZ feature on the HH3K and never had a problem with any of those.

One of these days when I have some time to kill, I may do a packet trace on the wire between the Eero Gateway and the HH3K to see if I can figure out what it is that the Eero is looking for in order to formally establish a connection, because it's obviously looking for something that no other router seems to care about.

As for speed tests, the Eero definitely hampers my download speeds — I get around 600Mbps maximum on my Gigabit Fibe connection — but what's weird is that upload speeds are actually fine at just under 1Gbps (which is what I'd expect considering it's only got a Gigabit Ethernet port). For my purposes, I don't really care as my Wi-Fi speeds aren't going to be any better than that on 802.11ac anyway — even with my 802.11ax Netgear router, only my Wi-Fi 6 capable devices (iPhone 11 Pro Max and 2020 iPad Pro) even got close to those speeds, and that's when they were sitting right next to the router. I've dual-homed my MacBook, with my Wi-Fi connected to the Eero and my Ethernet connection going directly to the Home Hub 3000 so I can ensure maximum download speeds. 

So just to close the loop on my comments above, I finally decided that the frustrations with Bell's "Advanced DMZ" weren't worth the headaches, since even though it's as fine 98% of the time, it was always that 2% that would potentially trip me up.

So I decided to simply assign the Eero to the "standard" DMZ, effectively creating a double NAT scenario — one where the Eero's "public" IP address is actually assigned by the Bell router on its own private subnet.

However, for me it's been working flawlessly in that configuration for several weeks now, with no problems at all dealing with routing traffic in and out — inbound Plex Media Server connections are all good, and even FaceTime, Skype, Zoom, and VoIP calls work fine, as do outbound OpenVPN tunnels. Don't get me wrong, double NAT was once a huge PITA, but most of the protocols that once had a problem with it were updated to deal with multiple layers of NAT years ago. To be fair, I've known that for a while, but I"ve also been doing this long enough that I'm still nervous from the "bad old days" of VPN and VoIP/video services that just couldn't cope with it. 

In fact, the biggest problem with most "double NAT" configurations is that you have to set up port forwarding on two routers if you want to let in inbound services, but that's mitigated by using the normal DMZ feature on the Bell router, since that will automatically forward all inbound traffic to the Eero's private IP address, at which point it doesn't really matter whether it's using a public IP or a "DMZ" private IP.