Connecting xFinity Modem to personal Router

Yes, tried that. But even after doing that, when I connect the router to the modem using port 1, it's not working. The port does work though, but only when connected directly to the laptop/desktop. I am wondering if there are any other additional settings we need to change on the modem or router for this to work. I have tried resetting the router and it still doesn't work.

@user_d5b4c6​  This one?  Archer A7 1750?  https://www.tp-link.com/us/user-guides/archer-a7&c7_v5/chapter-4-set-up-internet-connection#ug-sub-title-2   

If you've got your gateway in bridge-mode already.  Disconnect the TP-link Ethernet cable.  Pull the power cord on your gateway, then plug it back in.  Wait for it to connect back up to Xfinity.

While still disconnected, reset the Tp-link (hold the reset button on the back until the power LED flashes).   It will reboot when that happens.  Plug the Ethernet back into your gateway. (WAN port on the TP-Link to gateway).  

Connect to the TP-Link.  On the TP-Link, Try the wizard -- chapter 4.  That should default to DHCP for IPV4, and get you going at least.  If that works, you can try the section on setting up IPV6.  I think it's off by default.  On the manual connection type for IPV6 select (DHCPv6/SLAAC).    You can verify that works by seeing if you got an IPV6 address for it, or just go to test-ipv6.com 

In bridge mode, your gateway will pass out one single external IP address, to one MAC address.  If you plug a laptop into it, and that works, then hot plug your router into it without a reboot or powercycle on the gateway, the router won't get an IP address.   The external IP address will still belong  to the laptop, not the router, so you'll find it doesn't work. 

Also in bridge mode, the Xfinity gateway itself will shift the management interface on the gateway to http://192.168.100.1 and you won't be able to access it by going to http://10.0.0.1  so be aware of that when you want to log into the gateway directly.  

Now you can actually use the TP-Link with the gateway in gateway mode (WiFi on the gateway active).  It's called a double nat.  The TP-Link WAN port will be assigned an internal address like any other device in the 10.0.0.X range.  It can work.  IPV6 might not in that arrangement.  It adds another "hop" and can cause other issues so network folks generally frown on that kind of setup.  You also have to be careful that the internal IP range the TP-Link passes out is a different subnet than 10.0.0.0/24, or disable the internal DHCP server on the TP-Link and set it to forward DHCP requests to devices that connect to it to your gateway (10.0.0.1).   Then it's running in more of an "access point" mode and not doing the routing.  

Yes. But let me clarify that a bit more here. Disabling bridge mode does work in disabling the wifi capabilities, but I am not able to connect the router to the modem.

After the disable the setting, the wifi goes off and I can only connect my laptop directly to the modem via an ethernet cable, but the same doesn't work for the router.

Thank you for clarifying. I apologize if this question seems too obvious, but you mentioned resetting the router without much success. Have you also tried resetting or power-cycling the Xfinity Gateway to the same effect?

@user_d5b4c6 That is great to hear! Was there anything else we can do to help today?