On Wed, 18 Apr 2007, Jethro R Binks wrote:
| This has been suggested before, and ACLs suggested for it.
|
| However, I have often wondered about its reliability? Do most
| well-behaved MTAs properly re-transmit only the refused recipients (second
| recipient and higher)? Are there cases where an MTA will try and submit
| all the recipients again on re-connecting? Is it a big enough problem to
| worry about?
We've run this in production for 3 or 4 years.
Given that folk who do greylisting encounter badly behaved MTAs, we should
in theory expect some problems.
However, as we only have two spam profiles, and the vast majority of users
are on the same profile (the default), the defers are pretty rare. Much
more rare than e.g for greylisting. Hence actual problems are rare.
I recall us encountering one badly-behaved site early on. IIRC they took
our 4xx to mean "permanent failure" and hence the sender got a bounce.
We simply whitelisted them (I'm sorry to say).
--
Chris Edwards, Glasgow University Computing Service
