Hello - I troubleshot this problem extensively with a packet capture spanning the vlan between the 2wire router and my DD-Wrt router.  (Used to run it on a wrt54G, and then upgraded to a buffalo router running dd-wrt, but problem still continued.)  I saw the drops coming from the ATT 2-wire router and had them replace it.  GREAT!! The problem no-longer occurred!  A few days later I realized I was no longer in DMZ+ mode, so switched things back around.   What do you know, the problem started re-occurring on me!   The issues are no packet loss, because TCP would retry.  The issue is with hung connection states.   I am not 110% sure if it is on the 2wire side, or the way dd-wrt interprets the DMZ+ mode configuration.  (Although my previous cable modem connection, with the public IP on the dd-wrt box NEVER had an issue)    I have been doing double port forwarding for the past 1.5 years now.  I do however plan to hook up a different firewall to the ATT box and turn on DMZ+ mode.  We will see if the issues re-occur.