Moxa Technologies EM-1240-LX user manual Local Host Packets

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EM-1240-LX User’s Manual

Configuring EM-1240-LX

Destination NAT (DNAT)—changes the first destination packet IP address

MASQUERADE—a special form for SNAT. If one host can connect to the Internet, then other computers that connect to this host can connect to the Internet when the computer does not have an actual IP address.

REDIRECT—a special form of DNAT that re-sends packets to a local host independent of the destination IP address.

C.Mangle Table—includes two chains

PREROUTING chain—pre-processes packets before the routing process. OUTPUT chain—processes packets after the routing process.

It has three extensions—TTL, MARK, TOS.

The following figure shows the IPTABLES hierarchy.

Local Host

Packets

Mangle Table INPUT Chain

Filter Table

INPUT Chain

Local

Process

Mangle Table

OUTPUT Chain

NAT Table

OUTPUT Chain

Filter Table

OUTPUT Chain

Incoming

Packets

Mangle Table

PREROUTING Chain

NAT Table

PREROUTING Chain

NAT Table

POSTROUTING Chain

Outgoing

Packets

Other Host

Packets

Mangle Table

FORWARD Chain

Filter Table

FORWARD Chain

Mangle Table

POSTROUTING Chain

4-4

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Contents First Edition, November EM-1240-LX User’s ManualCopyright Notice Table of Contents Chapter EM-1240-LX Device API Introduction Product Features Package ChecklistOverview EM-1240-LXHardware Specifications Product SpecificationsSoftware Specifications EM-1240 Development Kit Embedded Module Hardware Block Diagram AppearanceEM-1240 Embedded Module EM-1240 Development Kit Dimensions LED Indicators Installing the EM-1240-LXWiring Requirements Connecting the Power Connecting Data Transmission CablesGrounding the EM-1240-LX Connecting to a Serial Device Connecting to the NetworkInternal SD Socket Reset ButtonAdditional Functions Serial Console PortReal-time Clock Getting Started Connecting the EM-1240-LX to a PC Powering on the EM-1240-LXConsole Port Telnet Default IP Address Default Netmask192.168.3.127 255.255.255.0 192.168.4.127 255.255.255.0Configuring the Ethernet Interface Dhcpcd -p -a eth0 & dhcpcd -p -a eth1 Ifconfig eth0Installing a Secure Digital SD Memory Card Developing Your Applications Installing the EM-1240-LX Tool ChainStep #mount -t iso9660 /dev/cdrom /mnt/cdromEM-1240-LX User’s Manual PATH=/usr/local/arm-elf/bin$PATH Compiling Hello.c#make Uploading Hello to the EM-1240-LX# chmod 755 hello #./hello Running Hello on the EM-1240-LXCflags = Make File Example CodeSoftware Package EM-1240-LX Software Architecture Journaling Flash File System JFFS2 Flash Context Flash Address Size Access controlAdditional information about JFFS2 is available at Bin Dev EM-1240-LX Software PackagePtyp0 Ppp Pio Rtc Ram1 Ram0 Null Kmem Mem Cua0 Console Tty ‰ Iptables ‰ NAT Configuring the EM-1240-LXEnabling and Disabling Daemons Example default enableAdding a Web Default Home Page addressLocal Host Packets Usage Define policy rules, and Append or delete rulesExamples Define policy for chain rules NAT Example Enabling NAT at BootupConfiguring PPPoE Configuring Dial-in/Dial-out ServiceDial-out Service Dial-in ServiceDynamic Driver Module Load/Unload How to Mount a Remote NFS ServerUpgrading the Kernel Ramdiskupkernel em1240-1.x.bin /ramdiskrebootUpramdisk Cd ramdiskUpramdisk Cd ramdisk Upgrading the Root File System & User DirectoryRamdiskbackupfs /ramdisk/usrdisk-backup User Directory Backup-EM-1240-LX to PCMirroring the Application Program and Configuration Loading Factory DefaultsAutostarting User Applications on Bootup Checking the Kernel and Root File System VersionsCat /etc/version FsversionEM-1240-LX Device API Buzzer RTC Real-time ClockUart Interface UC Finder Windows UC Finder EM-1240-LX User’s Manual UC Finder EM-1240-LX User’s Manual UC Finder Linux UC Finder Busybox µClinux normal command utility collection System CommandsFile manager EditorProcess NetworkOther Moxa Special UtilitiesSnmp Agent with MIB II & RS-232 Like Group Ip MIB Tcp MIB Udp MIB Snmp Agent with MIB II & RS-232 Like GroupRFC1317 RS-232 like group supported variables Rs232 MIB Snmp MIBEM-1240-LX FAQ Service Information Following services are provided Moxa Internet ServicesMoxa Product † EM-1240-LX Serial Number Problem Report FormProduct Return Procedure