Could you please retest your configuration by opening the ports with the "Virtual Servers" menu instead of "Port Forwarding" ?
Leolo:
I see no need to retest using Virtual Server to map the ports; as I noted in the original post, merely disabling the port forwarding rule was enough to let the traffic through. I repeat: nowhere did I specify that the ports be open; the incoming traffic should have been blocked by the firewall. Yet, it passed through. I first suspected a meddling ALG, but now a simpler explanation seems to be that my VoIP box initiated traffic to cause the right port mappings to be created.
So, you seem correct in thinking that your eMule problem is related to mine. It seems to be a case of Port Forwarding gone so wrong that it should have been called Anti-Port Forwarding.
My ATT Callvantage D-Link DVG-1120M stop connecting when i upgraded the FW to 1.20 also. Setting the 'UDP Endpoint Filtering' and 'TCP Endpoint Filtering' to 'Endpoint Independent' solved this.
optionstr8dr:
Thanks for the tip, but let us be clear: this is not a solution. Endpoint Filtering is
suppossed to have no effect where ports have been manually mapped; manual mapping should always take precedence. Not to mention that you have hurt your security by going to a full-cone NAT (I recommend reverting at least the TCP setting, if your VoIP box does not need it).
i too have VoIP problem
it started after 1.10 i think for me 
cant use telephone witch is annoying
dlink needs to fix DMZ, i got it working there but broke it again
the DMZ zone should be fully open, no packets should be blocked at all regardless of type
wiak:
Which version
broke it again? Did you disable SIP ALG? What VoIP hardware/provider are you using?