Ok... an update:
The 1.0.7 firmware did not solve the "connection tracking table full problem", however it is stable and does have a couple new features. I have now reconfigured the router firewall and that seems to have solved the problem (normally, connection locks up after 16-24 hours, now I have been running for 3 days with no issues).
Having examined the router firewall log, I'm guessing the problem lies with other p2p clients trying to initiate connection to me on various ports (other than those my p2p client is listening on). Previously the router was set to forward everything, but many of the packets received on arbitrary ports would have simply been dropped by the firewall on my pc, unknown to the router and hence filling up the NAT tracking table.
My solution is to set the default firewall policy on the router to DROP, and create a blanket rule to allow everything (ports 1-65535) OUT from my side. Also, ensure the "reverse direction" tick box is checked, since this appears to mirror the linux iptables ESTABLISHED connection state, so any connection established from my side allows traffic back in as well. I actually had problems with this check box not saving it's state when I tried to enter a custom rule, so I used one of the built-in rules (e.g. DNS) which already had the box checked, and customised that instead. Finally, I just created pinholes in the firewall to allow new connections from outside for services I wanted to expose - e.g. http, and also for the ports my p2p client is actually listening on to allow other leaf nodes to connect, but only on the allowed port(s).
As always, your mileage may vary.
hth
