Download Moxa C Programmable RTU Controllers User`s Manual

Moxa C Programmable RTU Controllers
Managing Communications
# Edit the rc.local file to make this shell startup automatically.
# vi /etc/rc.d/rc.local
# Add a line in the end of rc.local /home/nat.sh
EXIF=‘eth0’ # This is an external interface for setting up a valid IP address.
EXNET=‘192.168.4.0/24’ #This is an internal network address.
# Step 1. Insert modules.
# Here 2> /dev/null means the standard error messages will be dump to null device.
modprobe ip_tables 2> /dev/null
modprobe ip_conntrack 2> /dev/null
modprobe ip_conntrack_ftp 2> /dev/null
modprobe ip_conntrack_irc 2> /dev/null
modprobe iptable_nat 2> /dev/null
modprobe ip_nat_ftp 2> /dev/null
modprobe ip_nat_irc 2> /dev/null
# Step 2. Define variables, enable routing and erase default rules.
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin
export PATH
echo “1” > /proc/sys/net/ipv4/ip_forward
/bin/iptables -F
/bin/iptables -X
/bin/iptables -Z
/bin/iptables -F -t nat
/bin/iptables -X -t nat
/bin/iptables -Z -t nat
/bin/iptables -P INPUT ACCEPT
/bin/iptables -P OUTPUT ACCEPT
/bin/iptables -P FORWARD ACCEPT
/bin/iptables -t nat -P PREROUTING ACCEPT
/bin/iptables -t nat -P POSTROUTING ACCEPT
/bin/iptables -t nat -P OUTPUT ACCEPT
# Step 3. Enable IP masquerade.
Dial-up Service—PPP
PPP (Point to Point Protocol) is used to run IP (Internet Protocol) and other network protocols over serial
connection. PPP can be used for direct serial connections (using a null-modem cable) over a Telnet link, and for
links established using a modem over a telephone line.
Modem and PPP access is almost identical through the RTU controller’s Ethernet port. Since PPP is a
peer-to-peer system, the RTU controller can also use PPP to link two networks (or a local network to the
Internet) to create a Wide Area Network (WAN).
NOTE
Click on the following links for more information about ppp:
http://tldp.org/HOWTO/PPP-HOWTO/index.html
http://axion.physics.ubc.ca/ppp-linux.html
The pppd daemon is used to connect to a PPP server from a Linux system. For detailed information about pppd
see the man page.
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