Moxa ioPAC 8020-5-M12-C-T [51/69] Setup 1 ethernet bridging for private networks on different subnets

Moxa C Programmable RTU Controllers Managing Communications

4-14

Example:

smtpclient –s test –f sender@company.com –S IP_address receiver@company.com

< mail-body-message

-s: The mail subject.

-f: Sender’s mail address

-S: SMTP server IP address

The last mail address receiver@company.com is the receiver’s e-mail address. mail-body-message is the

mail content. The last line of the body of the message should contain ONLY the period ‘.’ character.

You will need to add your hostname to the file /etc/hosts.

OpenVPN

OpenVPN provides two types of tunnels for users to implement VPNS: Routed IP Tunnels and Bridged

Ethernet Tunnels. To begin with, make sure that the system has a virtual device /dev/net/tun. If not, issue

the following command:

# mknod /dev/net/tun c 10 200

An Ethernet bridge is used to connect different Ethernet networks together. The Ethernets are bundled into one

bigger, “logical” Ethernet. Each Ethernet corresponds to one physical interface (or port) that is connected to the

bridge.

On each OpenVPN machine, you should generate a working directory, such as /etc/openvpn, where script

files and key files reside. Once established, all operations will be performed in that directory.

NOTE

Network interface definition may be different in in different product lines. For

ioLogik W5348 series, eth0 =

ppp0(WAN)

、eth1 = eth0(LAN)

In the following examples, the OpenVPN A and B represent two Moxa RTU controllers. Note the network

interface definition may be different in different product lines. For ioLogik W5348 series, “eth0” in the example

will be ppp0(cellular WAN), and the “eth1” in the example will be the eth0(LAN)

Setup 1: Ethernet Bridging for Private Networks on Different Subnets

1. Set up four machines, as shown in the following diagram.

Host A (B) represents one of the machines that belongs to OpenVPN A (B). The two remote subnets are

configured for a different range of IP addresses. When this setup is configured to a public network, the

external interfaces of the OpenVPN machines should be configured for static IPs, or connect to another

device (such as a firewall or DSL box) first.