asadlive84/bridge-connection-with-two-namespace-with-google-ping

Create Bridge with two name space and ping google IP

First we have to install these tools in our system

ok start.....

sudo apt update

sudo apt install iproute2

sudo apt install net-tools

sudo apt install iputils-ping

sudo apt install iptables

Now we are creating two name space

sudo ip netns add red

sudo ip netns add green

We can check our namespace list

sudo ip netns list

Now we create bridge

sudo ip link add my-bridge type bridge

Now configure bridge

sudo ip link set my-bridge up

sudo ip addr add 192.168.0.1/16 dev my-bridge

this step we are creating two virtual eth cable

sudo ip link add veth-red type veth peer name veth-red-br

sudo ip link add veth-green type veth peer name veth-green-br

We have created two virtual cable. Both cable has two side. Now we will be trying to connect one side with namespace then another side we will try to connect with bridge like this.

now set

sudo ip link set veth-red netns red

sudo ip link set veth-red-br master my-bridge

sudo ip link set veth-green netns green

sudo ip link set veth-green-br master my-bridge

now we UP both side of cable

sudo ip netns exec red ip link set veth-red up

sudo ip netns exec green ip link set veth-green up

sudo ip link set veth-red-br up

sudo ip link set veth-green-br up

we are setting a IP address each of namespace

sudo ip netns exec red ip addr add 192.168.0.2/16 dev veth-red

sudo ip netns exec green ip addr add 192.168.0.3/16 dev veth-green

we are checking veth is down or up

sudo ip addr

we hope everything is UP

now we can ping namespace to another name space like this

sudo ip netns exec red ping 192.168.3 -c 3

sudo ip netns exec red ping 192.168.1 -c 3

sudo ip netns exec green ping 192.168.2 -c 3

sudo ip netns exec green ping 192.168.1 -c 3

now are are trying to ping our root IP address

sudo ip netns exec red ping 10.1.42.245 -c 4

if stuck or network unreachable, now have to check our IP table

sudo ip netns exec red route

sudo ip netns exec green route

we have to set default network gateway

sudo ip netns exec red bash

add default route

sudo ip route add default via 192.168.0.1

route

exit commands

exit

sudo ip netns exec green bash

add default route

sudo ip route add default via 192.168.0.1

exit command for exit from green namespace

exit

again are are trying to ping our root IP address

sudo ip netns exec red ping 10.1.42.245 -c 4

To add SNAT Rule at Host side

sudo iptables -t nat -A POSTROUTING -s 192.168.0.0/16  -j MASQUERADE

or

sudo iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o eth1 -j MASQUERADE

Explaining this code

-t nat: Specifies the "nat" table in iptables.
-A POSTROUTING: Appends the rule to the POSTROUTING chain.
-s 192.168.0.0/24: Specifies the source IP addresses (your local network).
-o eth1: Specifies the outgoing interface (connected to the internet).
-j MASQUERADE: Specifies the action to take, which is MASQUERADE (NAT).

sudo iptables -t nat -L -n -v

Putting it all together, the command sudo iptables -t nat -L -n -v is asking iptables to list all the NAT rules in the "nat" table, displaying numerical addresses, and providing verbose output with detailed information about each rule, such as packet and byte counts. This can be helpful for understanding the current configuration and activity of the NAT rules on your system.

sudo iptables --append FORWARD --in-interface br0 --jump ACCEPT
sudo iptables --append FORWARD --out-interface br0 --jump ACCEPT

These rules enabled traffic to travel across the br0 virtual bridge.These are useful to allow all traffic to pass through the br0 interface without any restrictions. However, keep in mind that using such rules without any filtering can expose your system to potential security risks. But for now we re good to ping!