Half-Grey-Listing (Update 01)

Posted on June 24, 2017 by Hendrik Jäger

Half-Grey Listing

Concepts of nolisting and greylisting should be known.

Imagine this setup:

example.org         IN  MX  05
example.org         IN  MX  50
example.org         IN  MX  99

All addresses are on the same host running exim. Exim would go through the whole process (almost – since most stuff is rejected anyway, one may want to optimize here) as normal, but will tempreject (almost – abuse@ and postmaster@ should probably be unfiltered, just to make sure) everything on and

Is anything wrong about this (WRT to RFCs)? What might go wrong?


It seems there are a few appliances that can’t properly deal with this setup:

I contacted all of them and the feedback I got so far:

I disabled the setup for now, though, too many broken sites out there …