The cause of NAT/Masquerading not perfomed

[liran tal]

Hey everyone,

What can be attributed as the cause for the problem of not performing an
NAT/Masquerade?
This is a basic scenario where a computer on the LAN attempts to reach a
computer beyond
the WAN port and what happens is that no Masquerading is being performed -
i.e: with a sniffer
I can see that the IP that was received is of the LAN computer (wasn't
replaced by the WAN IP address).

I can answer the question above with several possibilities:
1. wrong iptables rules
2. no NAT support compiled in kernel (or as module)
3. (bad network driver?)

I've had this problem with a kernel 2.4 and now I migrated completely to
kernel 2.6 (2.6.10)
and still encounter this problem.

Any comment on this issue would mean alot to me.

Regards,
Liran.