I tested this with another user in #dd-wrt IRC channel who had the SVN version he firmware on but had no port forwarding enabled (only had Ident configured) and he was able to dcc to me which I do not think should of worked. I am sure that when I flashed it to v24sp1 that I did the 30/30/30 reset. This router was power cycled several time wit dd-wrt v24sp1 installed. I never used ipTables when I was using dd-WRT firmware. When I had dd-wrt v24sp1 on this router I had no DMZ configured (I checked that). If I try a DCC chat with a friend then it is blocked when there is no Portforwarding and UPnP is disabled.This is because the connection is initiated on the WAN side of the router and since there is no port forwarded the connection fails. I went back to the original Linksys firmware to make sure that I was not halluncinating. Make sure DMZ for that IP addr is not enabled Perhaps there's an entry in iptables that carried over from before your upgrade and it just isn't showing up on the GUI. Think I will have to revert back to either v24rc7 or the original Linksys firmware for this router as I do not want these open ports.

This router has also by default still has UPnP disabled. As well this router has been power cycled several times. Yes I have gone into the port forwarding (both tabs) and there is nothing set in either one and I have made sure by clicking on Apply Changes and Save buttons on both screens. Are you sure you applied any changes you saved and/or performed a soft reset? Is no one else here using mIRC and dcc or is no one seeing this firmware letting unauthorized traffic through the router?

Mirc dcc port forwarding att