Re: [apps-discuss] draft-santos-smtpgrey-02: SMTP Service Extension for Greylisting Operations

[Ned Freed <[e-mail]>]

> On Sat, Feb 1, 2014 at 10:39 AM, Hector Santos <[e-mail]> wrote:

> > For our own implementation and deployments of WCSMTP.
> >
> > No collections from other packages was made from a client standpoint.
> >

> Does anyone else have current or planned implementations of this draft
> they'd like to discuss?

We see greylisting as something best done by a milter, so we're unlikely to
implement direct support in our MTA. That said, a milter has the ability to set
the SMTP response string to anything it wants. The only problem a milter would
have is changing the EHLO response to include the GREYLISTING extension. AFAIK
that is not a milter capability. We have a way to do that outside of milter but
I don't know if other milter-supporting MTAs do.

> > Many Greylisting servers do issue a time hint in their 45x greylisting
> > responses in various forms.   We can only speculate if other clients are
> > parsing this non-standard information and leveraging it for their outbound
> > mail retry scheduling logic.  Our client parses for the common format seen
> > out there, including the proposed format.
> >

> Can you point to some of the server implementations that do this?  Are they
> following the syntax in this draft?

milter-greylist has the ability to return SMTP responses containing the retry
time. The format is settable, so it should be able to generate something that
conforms to this RFC. 

There are various other milters that support greylisting; I don't know about
their capabilites.

				Ned