Automatically-mapped port closes after waking up from sleep

[psmisc]

Hi,

I am using Transmission with the "Automatically map port" option checked, so that I don't have to manually map the port on my router. However, every time my computer goes to sleep with Transmission left opened, when I wake up it says port closed in preferences. Restarting the program or the router don't work, I have to reboot my computer for the port to open up again. Randomizing doesn't work either.

I was wondering if this is a common scenario? Is there something I didn't configure correctly?

Oh, my router is Trendnet TEW-432BRP, I think it uses UPnP, and I am using 10.6 on an Intel Mac Mini.

Thanks!

Will

[psmisc]

Have you tried checking 'System sleep: Prevent computer from sleeping with active transfers' in Preferences>Network?

Yes I have, and it doesn't go into sleep when it's transferring. The problem is I sometimes I put it to sleep at night out of habit.