R6700 Port Forwarding Not Working

> c. My router is connect to a modem-router.  My modem-router is bridged
> to my router.

   What, exactly, is this "a modem-router"?  "bridged" is a specific
technical term.  Do you mean that the R6700 (WAN/Internet port) is
connected to this "a modem-router" (LAN port), or that the "a
modem-router" is in bridge mode, so that it's acting as only a modem, or
what?

> d. I believe it to be private but I am not sure.

> [...] (Is the WAN/Internet IP address of the R6700 a private or public
> address?  If in doubt, report at least the first two octets ("a.b" out
> of "a.b.c.d").)

   For access from the outside world to work, you'd generally want the
port forwarding configured on the outer router (closer to the ISP), and
cascading a second (inner) router would make things more complicated
("double NAT").

   To avoid cascading multiple routers, the two usual schemes are:

      1) Configure the modem+router as modem-only (also known as "bridge
         mode"), and do all the serious work on what had been the inner
         router (R6700).

      2) Use the modem+router as the main router, and configure the
         R6700 as a wireless access point.

   Either scheme leaves you with one router and one LAN.  Port
forwarding is configured on the one (remaining) router, and there's no
second router to cause trouble.  Which to choose may depend mostly on
which router has a nicer feature set.

> I have just been port forwarding through my router's configuration
> under the default gateway.  As to this, I do not have an address
> reservation if you are speaking about a static IP.

   You lost me.  With two routers, "my router" is a little ambiguous.
Copy+paste of some actual port-forwarding rules would be clearer than
any explanation of what you think they're supposed to be doing.

   Port-forwarding rules include a target (server) IP address.  If your
server is not at that address, then port forwarding is doomed.  The
server address can be static (assigned in the server's IP
configuration), or it can be a reserved dynamic (DHCP) address, so that
the router (DHCP server) always gives it the same address.

> [...] If you mean can I connect to said server locally (LAN), then yes
> I am able to.

   Yup.  That sounds good.  The problem may be confined to port
forwarding.  (And, perhaps, the cascaded routers which complicate port
forwrding beyond reasonableness.)