Moxa Technologies UC-7110 NAT Example, # iptables -A Input -i eth0 -p tcp --dport 25 -j LOG

UC-7110 Series User’s Manual Configuring UC-7110

Append or delete rules:

Usage:

#iptables [-t table] [-AI] [INPUT, OUTPUT, FORWARD] [-io interface] [-p tcp, udp, icmp, all] [-s IP/network] [--sport ports] [-d IP/network] [--dport ports] –j [ACCEPT. DROP]

-A:	Append one or more rules to the end of the selected chain.
-I:	Insert one or more rules in the selected chain as the given rule number.
-i:	Name of an interface via which a packet is going to be received.
-o:	Name of an interface via which a packet is going to be sent.
-p:	The protocol of the rule or of the packet to check.
-s:	Source address (network name, host name, network IP address, or plain IP
	address).
--sport:	Source port number.
-d:	Destination address.
--dport:	Destination port number.
-j:	Jump target. Specifies the target of the rules; i.e., how to handle matched packets.
	For example, ACCEPT the packet, DROP the packet, or LOG the packet.

Examples:

Example 1: Accept all packets from lo interface.

# iptables –A INPUT –i lo –j ACCEPT

Example 2: Accept TCP packets from 192.168.0.1.

# iptables –A INPUT –i eth0 –p tcp –s 192.168.0.1 –j ACCEPT

Example 3: Accept TCP packets from Class C network 192.168.1.0/24.

# iptables –A INPUT –i eth0 –p tcp –s 192.168.1.0/24 –j ACCEPT

Example 4: Drop TCP packets from 192.168.1.25.

# iptables –A INPUT –i eth0 –p tcp –s 192.168.1.25 –j DROP

Example 5: Drop TCP packets addressed for port 21.

# iptables –A INPUT –i eth0 –p tcp --dport 21 –j DROP

Example 6: Accept TCP packets from 192.168.0.24 to UC-7110’s port 137, 138, 139

# iptables –A INPUT –i eth0 –p tcp –s 192.168.0.24 --dport 137:139 –j ACCEPT

Example 7: Log TCP packets that visit UC-7110’s port 25.

# iptables –A INPUT –i eth0 –p tcp --dport 25 –j LOG

Example 8: Drop all packets from MAC address 01:02:03:04:05:06.

# iptables –A INPUT –i eth0 –p all –m mac –mac-source 01:02:03:04:05:06 –j DROP

NAT

NAT (Network Address Translation) protocol translates IP addresses used on one network into different IP addresses used on another network. One network is designated the inside network and the other is the outside network. Typically, UC-7110 connects several devices on a network and maps local inside network addresses to one or more global outside IP addresses, and un-maps the global IP addresses on incoming packets back into local IP addresses.

NOTE Click on the following link for more information about iptables and NAT:

http://www.netfilter.org/documentation/HOWTO/NAT-HOWTO.html

NAT Example

The IP address of all packets leaving LAN1 are changed to 192.168.3.127 (you will need to load

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