The
HG612 is set to get an IP address from
TalkTalk. It will thus allow any connected device access to the Internet because it has its DHCP server enabled. It will hand out an IP address via DHCP, on its own subnet, i.e. 192.168.2.x.
What I have done is to connect my
TP-LINK WDR3600 router to it via ethernet. The
TP-LINK router requests an IP address from the
HG612 on its local subnet, i.e. 192.168.2.x (in this case). The
TP-LINK router can thus connect to the Internet and any connected device will receive an IP address on the TP-LINK router's subnet, i.e. 192.168.1.x (in this case), as it also has its DHCP server enabled.
The
TP-LINK router has a static route setup so the
HG612 can be accessed via the TP-LINK router, at the address 192.168.2.254. This means I can use only one cable instead of two (if the
TP-LINK was getting an IP address from
TalkTalk, with the HG612 just acting as the modem).
Does that make sense?
