I am not 100% certain that I need to use True Bridge mode . I am not wanting to use the router functionality that is built into the modem. I have some setting already set up on a secondary router. If i am wanting to use my other router would I need to switch to true bridge mode on the modem?
The Comcast Gateways (CG) can be put into True Bridge Mode (TBM) and when doing so, it disables ALL internal routing with the ONLY exception of pass the CG WAN address to the second router's WAN interface. This implementation would mean that ALL your internal network routing would be performed through your second router's routing and processing. Lastly, if your CG is in TBM you cannot use any Comcast static IP address because that routing is also disabled in TBM.