2

based on this sample guide link:
http://ubuntulinux.co.in/blog/ubuntu/nat-configuration-with-iptables-in-ubuntu/

with this code: 

iptables –append FORWARD –in-interface eth1 -j ACCEPT

it means that "All PC’s on the private office network should set their “gateway” to be the local private network IP address of the Linux gateway computer."

How can we make our ubuntu server router gateway mode to router mode? In order our private networks is visible from other networks or different subnet.

Scenario:

                             +---+        
                   eth1-*.1.2| S |           +----------+
 *1.1router===switch=========|   |           |          |------PC1
               ||            | / |private net|  switch  |------PC2
               ||            |   |===========|          |------PC3
               ||            | R |eth0-*.0.1 +----------+
               ||            +---+
             *.1.3
              Router
               ||            
               ||
             *.7.1
          other network

S/R: Server as Router
192.168.x.x
eth1: connection from the internet/other network
eth0: internal/private network
PC1,PC2,PC3: w/ ip add .0.x

ckknight
  • 303

1 Answers1

1

You'll need to turn on IP forwarding if your static routes are already in place. To do that run sudoedit /etc/sysctl.conf and look for the following segment:

# Uncomment the next line to enable packet forwarding for IPv4
#net.ipv4.ip_forward=1

Do as it says and uncomment the second line so it looks like:

net.ipv4.ip_forward=1

Save and exit. Then run sudo sysctl -p /etc/sysctl.conf to reload the configuration. You might then have to reload the networking stack (sudo restart networking) but after that your 192.168.7.x machines should be able to reach 192.168.0.*

Oli
  • 299,380