My home network consists of a cable modem provided by the ISP, which is connected to a switch, from the switch 1 cable runs to the digital tv decoder/recorder also provided by my ISP and another cable goes into the WAN port of my router. ALL other computers are attached to the router with NAT, DHCP. The sole reason of the switch between the modem and the router is that the digital tv decoder/recorder needs a public ip to function, it doesn't work behind NAT, even with all ports forwarded...
The whole setup looks like this:
[isp] (dhcp) | [modem] | [switch] | +--[digital tv] | +-- (wan port) -- [router] (dhcp) | +--[pc] | +--[pc] | +--[pc]
The issue with this setup is that when clients attached to the router are configured as dhcp clients, they sometimes get an ip from the router's dhcp server in the NAT domain, as desired, but sometimes they get a public ip from the modem depending on which dhcp server, the modem's or the router's, reponds first.
The modem seems to hand out 2 ip's in the public domain 84.xxx.xxx.xxx and this functionality can not be disabled as far as I know. This is not desired because other computers which are behind NAT are unreachable in this case.
Currently I give the clients attached to the router a static ip in the NAT domain as a workaround, but I am looking for a solution so that clients would always get an ip address from the router's dhcp server if they are configured as dhcp clients.
Is this possible??