There are several ways to do this, and several meanings of "clear IPs
passing through".

If you want to turn m0n0wall into a bridging firewall, that should be
fairly simple.  I'm going to be doing it soon on one of our networks,
and I'm not absolutely positive I have this right, so I'll post to the
list and see if I'm being helpful or not - that way we both get advice
:)

1) Disable NAT - Under Firewall/NAT/Outbound, Tick "Enable advanced
outbound NAT", and don't add any rules.
2) Enable filtering bridge mode - Under System/Advanced, tick "Enable
filtering bridge"
3) You may need to enable Proxy ARP on the WAN interface over your
internal IP range, depending on your routing arrangements.
4) Add firewall rules as per normal.

Of course, I could be wrong - I haven't had the chance to play with
m0n0wall in this configuration.  Anyone want to confirm this for me?

Regards,
William Bryson

Original: Sergio Miranda [mailto:soporte at telcorp dot com dot ve] 
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Hi, There is any way to disable NAT from LAN interface to WAN interface,
I just need clear IPs passing throught, it is possible?

Thanks in advance.

Best Regards,

SM