I have a Cisco DPC3825 DOCSIS 3.0 Gateway router. I'm trying to set up a static IP in order to forward port 22 for SSH. I did this by setting etc/network/interfaces to this
auto eth0 iface eth0 inet static address 192.168.1.178 netmask 255.255.255.0 gateway 192.168.1.1 dns-nameservers 188.8.131.52 192.168.1.1
However, my router's IP is 192.168.0.1, and so it wont let me forward to any IPs outside the range 192.168.0.xxx. So I changed the above to
auto eth0 iface eth0 inet static address 192.168.0.178 netmask 255.255.255.0 gateway 192.168.0.1 dns-nameservers 184.108.40.206 192.168.0.1
However, this has the strange effect that I can no longer log into my router from behind. It just says 'unable to connect, firefox can't establish a connection to the server at 192.168.0.1'.