Moxa KM-2430-T [32/52] Nat snat

ioPAC RTU Software RTU Communications

4-7

Example 7: 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

NOTE

In Example 7, remember to issue the command #mo

dprobe ipt_mac first to load module ipt_mac.

NAT (SNAT)

NAT (Network Address Translation) protocol translates IP addresses used on one network to different IP

addresses used on another network. One network is designated the inside network and the other is the outside

network. Typically, the ioPAC RTU controllers connect 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 links for more information about iptables and NAT:

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

-HOWTO.html

The IP address of LAN1 is changed to 192.168.127.254 (you will need to load the module ipt_MASQUERADE):

1. #echo 1 > /proc/sys/net/ipv4/ip_forward

2. #modprobe ip_tables

3. #modprobe iptable_filter

4. #modprobe nf_conntrack

5. #modprobe iptable_nat

6. #modprobe ipt_MASQUERADE

7. #iptables -t nat -A POSTROUTING -o eth0 -j SNAT --to-source 192.168.127.254

8. #iptables -t nat -A POSTROUTING -o eth0 -s 192.168.126.0/24 -j MASQUERADE