by josh » Fri Jan 17, 2014 10:00 pm
We have a little underpowered box servicing over 6.5 million disposable email addresses spread over dozens of domains. Beyond the actual disposable addresses, the Rumpelstiltskin attacks add a tremendously larger number of non-addresses (each Rumpelstiltskin attack repeated for each of the domains).
Without outer defenses like the reverse lookup check culling hits from the vast bot armies, our box would go down almost instantaneously - have a look at the graveyard of former disposable address services that fell to the same hordes.
Also, I can say that when we move from one ISP to another, getting a new set of IP addresses, in the period between the move is complete and when the ISP sets up the proper PTR records, we get a *lot* of failures - this check is not uncommon at all.