I have a linux home router, with 3 nic's,
eth0: for internet
eth1: for the first local subnet
eth2: for the second local subnet
It runs nat from the 2 local cards to the internet, with :
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
On slackware i had to add routes between the 2 local subnets manually if i wanted them to access each other.
#/sbin/route add -net 192.168.1.0 netmask 255.255.255.0 gw 192.168.3.1 metric 1
#/sbin/route add -net 192.168.3.0 netmask 255.255.255.0 gw 192.168.1.1 metric 1
On ubuntu however this routing is on by default, and i don't want that at the moment. (second subnet is for a different apartment, i don't want them browsing my shares/network printer etc).
How do i turn this off?