For some bizarre reason, ufw is *sometimes* preventing HTTP POST requests. GETs work normally, but POSTs hang forever. I know it's ufw because everything goes back to normal if I turn it off. Also, if I restart networking, it solves the problem temporarily. I don't have to do anything to ufw for it to start misbehaving. It can work normally for days before it starts blocking POSTs for no good reason.
Any clue what it might be?