Networking 101 : Veth network interfaces, Linux virtual bridges and Namespaces
Creating namespaces:
We can create namespaces using the below command:
We can check if the namespaces were created using the below command:
To display the network interfaces in the namespace_1 for example, we use:
The "ip link" command is executed inside the "namespace_1".
Connecting two namespaces:
In order for the namespace_1 and namespace_2 to communicate, we create a connection (comparable to a physical network cable) and we connect one end to namespace_1 and the other end to namespace_2.
Creation of the "veth" virtual cables:
We, then connect end_1 to namespace_1:
We give each "virtual cable" end an IP address:
To check the connection, we try to ping namespace_2 from namespace_1:
Remark:
To delete a cable we use the below command (deleting one end of the connection, deletes also the other end):
Using the Linux bridge:
When we want to connect more than two namespaces, we would need a bridge. Linux offers us a virtual bridge.
We create a virtual bridge "bridge_1" using:
We check if the bridge was created using the below command. On the host "bridge_1" appears as an interface:
Creating the namespaces links to the bridge:
We attach the link namespace_1_end_1 to namespace_1:
We, then attach bridge_end_1 to the Linux bridge bridge_1:
We, then attach bridge_end_2 to the Linux bridge bridge_1:
We assign IP addresses to the links:
Finally, we enable the links on the namespace:
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