05 Configuring a private network on Linux Cloud Servers

Topics:

• Before proceeding
• Temporarily configuring the private network on Linux
• Permanently configuring the private network on Linux
• What to do after configuration

Before configuring the private network in the operating system:

• connect the Cloud Server to the Virtual Switch;
• identify the network interface connected to the Virtual Switch;
• choose the private IP address to configure on the network interface in the operating system and the corresponding netmask, following the private network addressing guidelines.

You can configure the network interface temporarily, for testing or verification purposes, or permanently.

The temporary configuration remains active until the next Cloud Server restart.

To temporarily configure the network interface:

• access the Linux Cloud Server via SSH or using the available console;
• run the following command:

  ifconfig <interface> <ip_address> netmask <netmask>

  where:

  • <interface>

    is the network interface connected to the Virtual Switch;

  • <ip_address>

    is the private IP address you want to configure;

  • <netmask>

    is the private network netmask.
• for example:

  ifconfig eth2 192.168.0.11 netmask 255.255.255.0

• verify the configuration by running:

  ifconfig <interface>

  for example:

  ifconfig eth2

The procedure for making the private network configuration permanent depends on the Linux distribution and version.

CentOS 5.x - CentOS 6.x

• run the following command:

  system-config-network

• in the graphical interface, use the arrow keys and the Tab key to select Device Configuration, then press Enter;
  
  
• identify the network interface connected to the Virtual Switch and press Enter;
  
  
• configure the private IP address and netmask in the corresponding fields, then confirm with OK, save with Save and exit with Quit.
  
  

CentOS 6.x - Alternative method

• open the network interface configuration file:

  nano /etc/sysconfig/network-scripts/ifcfg-eth0

  replacing eth0 with the network interface you want to configure;
• configure the interface parameters. For example:

  DEVICE=eth0
  NM_CONTROLLED=no
  ONBOOT=yes
  TYPE=Ethernet
  DEFROUTE=yes
  IPV4_FAILURE_FATAL=yes
  IPV6INIT=no
  NAME="System eth0"
  BOOTPROTO=none
  IPADDR=192.168.0.11
  NETMASK=255.255.255.0

• save the changes with CTRL+O and close the editor with CTRL+X;
• if necessary, check the network configuration in the following file:

  nano /etc/sysconfig/network

• to apply the changes, run:

  /etc/init.d/network restart

Repeat the procedure for all Linux Cloud Servers you want to connect to the private network, assigning each network interface a unique private IP address belonging to the same network and using the corresponding netmask.

After configuring the private network on the Cloud Servers, verify the private network configuration and check that the Cloud Servers can communicate correctly using their respective private IP addresses.

Related guides:

Configuring and managing a Virtual Switch

Creating a private network between multiple Cloud Servers

Verifying the private network configuration

Connecting to Cloud Servers using private IP addresses