NAT SNAT DNAT Problems New to IPTABLES and linux networking

Okay I am totally new to IPTables and networking in Linux. I have a linux box hooked to my network and want to change the source and destination address of certain packets for VOIP purposes. All I have done so far is created a script for IPTables and activated it, but it doesnt seem to do anything. Here is my script as follows:

#!/bin/bash


iptables -t filter --flush
iptables -t nat --flush
iptables -t mangle --flush

iptables -t filter --delete-chain
iptables -t nat --delete-chain
iptables -t mangle --delete-chain

iptables --policy INPUT DROP
iptables --policy OUTPUT DROP
iptables --policy FORWARD DROP
iptables -t nat --policy POSTROUTING ACCEPT
iptables -t nat --policy PREROUTING ACCEPT

iptables -A INPUT -i lo -j ACCEPT
iptables -A OUTPUT -o lo -j ACCEPT

iptables -F PREROUTING
iptables -A POSTROUTING -p all -s 10.22.92.111 -o eth0 -j SNAT --to 172.24.9.211
iptables -A PREROUTING -p all -d 172.24.9.211 -i eth0 -j DNAT --to 10.22.92.111

service iptables status

Okay, How do I check to see if Network Filtering is turned on and do I need to use IP forwarding? Any help appreciated...

Thanks,

Justin Curtis

What exactly do you want to do? Are you sure it's not IP masquerading you want?

I want to change the Destination and Source address of Certain Packets

I am losing certain packets when I try to access a remote network from my house. This is because there is a router in between that I do not have access to and it is blocking my packets because they are not on its network. I want to change the destination and source address of certain packets before they cross that router so they can make it back over to my network.