routes are killing me - how to?

[Keary Suska]

on 11/6/02 7:44 PM, jeglin@4pi.com purportedly said:

>> echo 1 > /proc/sys/net/ipv4/ip_forward
>> 
>> This allows, as the name implies ip forwarding. Most basic NAT.

I believe that this statement is false. I have never heard of IP forwarding
doing anything except forwarding a packet not destined for its network to
the appropriate gateway in its routing table. To say that setting ip_forward
sets up a basic router, would be true.

NAT requires much more than simply getting a packet from A to B. It must
also map between internal addresses (usually by using ports). AFAIK, any
form of NAT or Masquerading requires IP Chains or IP Tables, or some other
software that can manage a NAT, and is in no way a default function of the
kernel and TCP/IP stack.

However, with this option set, and considering that an interface has been
set up as the gateway for the 192.X network, you will be able to ping 192.
addresses, but 192. won't be able to ping outside their network.

Keary Suska
Esoteritech, Inc.
"Leveraging Open Source for a better Internet"