I've had this problem for a few months now and just fixed it. It was a router issue. My NAT settings were too strict.
I just changed my router's settings so that the TCP Endpoint filtering is a little less strict. I changed it from Port and Address Restricted to just Address Restricted, and the problem went away. Confirmed using DA1, DA2, and ME2.
This is what my router's help files have to say about NAT endpoint filtering:
NAT Endpoint Filtering
The NAT Endpoint Filtering options control how the router's NAT manages incoming connection requests to ports that are already being used.
Endpoint IndependentOnce a LAN-side application has created a connection through a specific port, the NAT will forward any incoming connection requests with the same port to the LAN-side application regardless of their origin. This is the least restrictive option, giving the best connectivity and allowing some applications (P2P applications in particular) to behave almost as if they are directly connected to the Internet.
Address RestrictedThe NAT forwards incoming connection requests to a LAN-side host only when they come from the same IP address with which a connection was established. This allows the remote application to send data back through a port different from the one used when the outgoing session was created.
Port And Address RestrictedThe NAT does not forward any incoming connection requests with the same port address as an already establish connection.
Modifié par Graye, 14 octobre 2011 - 05:53 .