So I've got a raspberry pi that bridges wlan0 and eth0 so an old xbox can have wifi, yay! The bridging happens at startup through a script I wrote that reads a file to decide whether or not to bridge. The issue is, I'd like to still be able to remotely access the pi. The bridging makes this difficult (impossible at the moment). The br0 interface can obtain an IP, as I showed here, but that doesn't respond to ping, etc. The thing is idle, so my current technique is to plug in a keyboard and monitor, login, change it to NOT bridge, then poweroff. I was thinking I could program a button to do all that, but I wonder if there's something better?
To add a separate IP address so you could log on, add this to your /etc/network/interfaces:
Of course, replace the placeholder in the address line with an appropriate IP address, different from the main one.
Do remember that the pi doesn't power off after a 'halt' or 'shutdown -h now' command. It just sort of hangs, and since the main controller stops running, the current drawn is often higher than when running at idle. The guy's comments above about using a GPIO pin to control a relay are valid solutions to your shutdown issues. My answer would possibly give you the ability to log in remotely without needing to attach everything.
Unless you're really worried about it, leave it running. Repeated cycling can cause SD card corruption, try to minimize them.