Does Xfinity Gateway act as unmanaged switch in bridge mode?

[Barryng]

My Xfinity XB8-T Gateway is in bridge mode. Switch port 4 (Orange) is connected to a Netgear RAXE300 wireless router/switch that provides a stronger and far superior Wi-Fi signal than the XB8-T did and completely solved a number of previously unresolvable connectivity issues with various Wi-Fi devices like door locks, wireless cameras, etc. Each of my three Xi6-A TV set top boxes are connected with an ethernet cable to the Netgear router's switch as ethernet has proven to me to work much more reliably than a Wi-Fi connection.

All three setup boxes work great except immediately after turning the TV and STB on. The set top boxes seem to take longer to start up and, without exception, provide an error message about an undefined but unexpected problem. Just acknowledging this dialog gets everything going OK. Nevertheless, every night we initially have error messages, no audio, etc. when starting a TV.

So, I tried an experiment and got an unexpected but good result. Instead of the Ethernet cables from each of the three set top boxes terminating in the Netgear wireless router's switch, I connected them to the unused ports on the XB8-T Gateway (in bridge mode). To my surprise, none of the startup glitches, I just described, occur anymore. Everything now starts up immediately and without a problem. Also, obviously, even though the XB8-T Gateway is in bridge mode, the integrated switch still works.

Although, I did not expect the XB8-T switch to work except for the orange port, it seems to work and work very well. However, does connecting the three set top boxes directly to the Gateway and its presumably unmanaged but functioning switch, present any security concerns for me? Is there anything else I do not know enough to ask about I should be aware of?

 

[Janus67]

If the devices are each getting a unique IP I'd say DHCP is still on for the gateway. I thought bridge was just for passthrough (and would have DHCP disabled), but I haven't used a supplied isp modem for decades.

I wouldn't worry about set top boxes as a security risk being plugged into the gateway.

And everything else on the network is still good to go I assume?

 

[Barryng]

Thanks. Yes, everything else on the network appears to be working fine, including the download/upload speeds on my ethernet connected desk top computer. Searching via Google I found stuff that states absolutely positively the Gateway switch is disabled except for the port with the orange stripe (that connects to the external Netgear device) and I have found stuff that states absolutely positively the Gateway switch is still operable. At least for the Xfinity XB8-T Gateway the switch obviously appears to still be functioning perfectly.

Interestingly, if I connect the set top boxes to the Netgear switch, all three have problems when I turn them on but after a delay and an error message or two work fine. All I did was to reconnect the Ethernet cables from the three set top boxes to the switch ports on the gateway, and they all immediately turn on without any issues. I suspect there is a setting in the Netgear switch that needs to be changed but I do not know enough about it to know what that might be.

 

[Barryng]

I discovered why the switch in the Comcast Gateway still works.: It is not in Bridge Mode, but the Wi-Fi feature is turned off. I set it up last February and I remember, obviously incorrectly, placing it in Bridge Mode, but when I took a look last night, I discovered it is not. I did enable Bridge Mode last night, but the Gateway locked up and a power reset did not help. That required a hard reset back to factory defaults which then required Comcast to reactivate it. So, to avoid more brain damage, I just turned off the Wi-Fi feature, reconnected each of the three set top boxes to the Gateway switch, and let well enough be. I hope that is not a mistake, but everything works very fast with no obvious issues and the Netgear Wi-Fi plays very well with the door lock, thermostat, garage door opener, door bell, etc.