> I know the problem with commercial recipients but I dont fully understand
it (running a mailserver
> for clients that dont like greylist, myself)
There are essentially two problems here that bother commercial email
traffic.
1. As you noted, some people like to use email as instant messaging,
quite legitimately. Greylisting can interfere with this, especially if you
have a setup that isn't good at recognizing prior legit mail from the same
source. (And even if it is working proplerly.)
2. It is an unfortunate fact of life that there are some unknown number
of mail programs out there that will for one reason or other effectively
treat or turn a tempfail into a permanent fail. In this case the mail is
lost, which is not good for business. There are some unknown other number
of programs that might only reply back after 24 hours or 3 days or some
such. Also not good for business.
Now, how 'real' is the second problem? Certianly if you google around you
find documented lists of programs that fail to respond correctly, and some
of these are known or strongly suspected to still be in use at various
companies. Maybe in reality this isn't a problem. But nobody is willinbg
to take the chance yet.
On the first problem, I've had any number of tech support sessions where the
only way the guy could contact me while debugging the problem with live
equipment was over email. So I'd ask him to check something, then get an
email reply back, then respond, etc. Often these sessions started from
someplace I had never received mail from before, and it could come from most
anyplace in the world, usually unrelated to where the person was physically
located. Greylisting would have been bad news on at least the initial help
request.
Loren
