In case you still don't have incoming connections, perhaps you also have firewall software installed that needs configuration...Depending on your exact configuration it is possible with the 3Com3C857 router that after a while you might be again without incoming connections...
... connects to a 3com3C857 gateway that acts as a DHCP Server that also manange ... domain 192.168.0.1 instead of 3com3C857 gateway IP 192.168.1.1 where all ...