Page Comparison

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• The Linux instance has a primary Ethernet interface (eth0) with address 10.2.0.8/24 and a public IP address (PubIP0PubIP-0). The default route points to this interface.
• The Linux instance has a secondary Ethernet interface (eth1) with address 10.2.0.9/24 which also has a public IP address (PubIP1PubIP-1).
• All firewalls on the operating system and cloud level are set to allow ICMP traffic to both interfaces.

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• A ping from an external host to the public IP address PubIP0 PubIP-0 of the primary Ethernet interface works.
• A ping from an external host to the public IP address PubIP1 PubIP-1 of the secondary Ethernet interface fails.
• A network trace on the cloud host shows that the ICMP packets to PubIP1 PubIP-1 arrive at the cloud instance on eth1 as expected, but there is no answer. The reason is that the answer follows the default route via the primary interface, and this traffic is blocked by the cloud provider.

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• The sample configuration assumes a CentOS 7 system and that the interface is configured outside the control of the NetworkManager.
• Should the NetworkManager be active, the plugin ifcfg-rh must be enabled in section main of the NetworkManager configuration file /etc/NetworkManager/NetworkManager.conf. It enables the NetworkManager to read and write ifcfg-files.
• After the initial creation of the ifcfg-file, the interface can be managed by the Charon-SSP Manager.
• For the full feature-set of the file-based network configuration, the network-scripts package is required.

To make the second interface usable for the Charon guest system, perform the following steps:

1. Add a second interface to your instance as described in the cloud-specific Getting Started guide and your cloud provider's documentation.
   
   
2. Log into the instance and become the root user (use: sudo -i)
   
   
3. Identify the names of the two Ethernet interfaces:
   # ip link show
   
   
4. Create an interface configuration file for the second interface.
   1. A file for the first interface may exist depending on the default of the cloud environment. In this case, you can copy  Example (use correct interface name for your configuration):
      # cp /etc/sysconfig/network-scripts/ifcfg-eth0 /etc/sysconfig/network-scripts/ifcfg-eth1


   2. If there is no file that can be copied, you must create the ifcfg-file for the new interface manually.
      
      
5. Edit this file to match the characteristics of eth1 (use correct interface name for your configuration). The private IP address used for this interface will be assigned to the Solaris guest. Therefore, configure the Linux Interface without IP address, similar to the example below.
   
   BOOTPROTO=none
DEVICE=eth1
NAME=eth1
ONBOOT=yes
TYPE=Ethernet
USERCTL=no
NM_CONTROLLED=no 
   
   Please note:
   On some cloud platforms, the automatic cloud-specific configuration prevents the entries in the ifcfg-file to take effect (for example on GCP). Please refer to your cloud-provider's documentation and the Network Interface Management section for additional information.       


6. Restart the network:
   # systemctl restart network
Please note: Should there be an error when executing this command, kill the DHCP client process and retry the command.

Basic Interface Configuration with NetworkManager

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• The interface names used in the following section are for illustrative purposes only. Please familiarize yourself with the interface naming conventions used in your cloud environment. 

• The sample configuration assumes a Rocky Linux 8.x system and that the interfaces are under the control of the NetworkManager.

• On some cloud platforms, the automatic cloud-specific configuration prevents the operating system configuration to take effect (for example on GCP). Please refer to your cloud-provider's documentation for additional information.

In such environments, you have different options to configure network interfaces for use by the guest system. The main options are the following:

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