Yes , you must replug the Ethernet cable or power the unit on and off to access it.
If you reboot your router it will cause this. I posted this issue and keep asking for a firmware update to fix the issues with the dns 320 and 325, but i dont think they will.
keep in mind it was 4 months from their last update, so they probably just forgot about it all together.
If they dont fix the problem when the product is new , they they probably arnt going to fix it in the future.