I have 1 NIC card with 2 ip address:
IP1 = 192.168.3.1/255.255.255.192
Network 1 = 192.168.3.0/255.255.255.192
IP2 = 192.168.4.1/255.255.255.248
Network 2 = 192.168.4.0/255.255.255.248
My question, how can workstations from network 1 reaches the
workstations in network 2 and vice versa using IPtables?
This really is not an IPTables issue as this is more a routing issue than it is a packet filtering issue. All you need to do to enable the ""routing would be to enable IP forwarding via one of these two methods:
sysctl -w net.ipv4.ip_forward=1
or
echo "1" > /proc/sys/net/ipv4/ip_forward
The only thing that IPTables might be interfering with this on would be if you have your default FORWARD policy to DROP. In that case you would need to do something like the following:
iptables -t filter -A FORWARD -i eth0 -o eth0 -j ACCEPT
Or if you want to be more specific and specify what subnets can forward you would need the following rules:
iptables -t filter -A FORWARD -i eth0 -o eth0 -s 192.168.3.0/24 -d 192.168.4.0/24 -j ACCEPT
iptables -t filter -A FORWARD -i eth0 -o eth0 -s 192.168.4.0/24 -d 192.168.3.0/24 -j ACCEPT
Grant. . . .
