Firewall/NAT

I currently have rules configured as follows:
- Allow LAN -> any
- Allow DMZ to anywhere *BUT* LAN
- Deny anything coming from WAN to DMZ and LAN

Pretty straightforward - however, when I'm running a ping from the M0n0wall's Web interface, I'm able to ping any node, regardless of the rules.  For example, even when I set my source interface as the DMZ interface, I am still able to ping nodes on the LAN (despite my rule denying DMZ traffic to LAN).  However, everything appears to be functioning normally when I try to access a LAN node from a DMZ node (fails, as expected).  Is this ping behavior normal when running it from the MW's Web interface?

Is this ping behavior normal when running it from the MW's Web interface?

Yes - the firewall rules do not apply to traffic originating from m0n0wall itself.