John Leslie wrote:
What would others like to see in a fix for graylisting?
I am not sure how much can be done. As you know, the reason why it
"appears" to work (or it does it job) is that its based on legacy
considerations (standard expectations and behavior of smtp senders).
But I may have a few items to consider:
Maybe this is more for 2821bis, is to emphasize proper or retry methods,
in particular GL compliant sender to reconsider how their 2nd retry is
done. That was one of the first things we had to change in our SMTP
client. Basically providing a variable frequency table. Otherwise, that
2nd attempt was delayed to the old once per hour default and we did
experiences an increase in reports about the rejects and not seeing
email until much later. We hardly see reports or hear of them since the
new frequency table as provided.
Possible some guidelines on the response code and text - making it official.
Suggestions about considering auto-whitelisting with local outbound mail
flagging outgoing addresses to help auto-whitelist an anticipated
response from them. Today, its normal practice during a support
incident for us to ask a customer for his email address to send an email
if we are planning to ask them to send us something. A 'permission
email' per se. That way they get auto-whitelisting.
I guess also some guidelines on the fine tuning of typical GL
parameters, such as using a class-c subnet (1.2.3.0) masking as part of
the triplet hash calculation. As you know, this addresses the sender
with outbound farms on the same subnet. In addition, other factors
such as a general rule of thumb for retaining records, etc, etc.
One other option to help reduce issues, is to only apply GL for incoming
addresses in a group of local domains, a spec or all. For example, for
our support system we only apply it to mail coming into to our corp or
support domains. Not all other locally hosted domains.
Note sure if this is direct SMTP material but may be useful as design
guidelines to consider for future GL implementations to maybe help
minimize impact.
Other than that, it just runs, and it does its job which an amazing
constant rejection rate of 60% - which I guess is the near standard rate
of bombardment by these braindead bulk spammers.
--
Hector Santos, CTO
http://www.santronics.com
http://santronics.blogspot.com