So ordb.org has been dead for awhile. If you had an inactive server that was using ordb.org as your Realtime Black-List server on that box and you bring it back up then you won’t accept email from anyone any more. Reason being is that every time your server goes to receive an email and does a lookup on an RBL if it cannot reach the RBL then it will receive no email. Furthermore if your server cannot communicate with the RBL server then you will reject mail. So while RBLs will save you from massive amounts of spam they can actually be used to attack your server. For example, the…