Thank you very much; I certainly have an AmavisD setup (Spamassasin, ClamAV
AntiVirus, etc.) behind this; I am just trying to cut down on false
positives while making as little a disruptive change as possible to the end
user.

I will try out your suggestion on #2.

Thanks again.

Regards,

Christopher Kurtis Koeber

-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Wietse Venema
Sent: Wednesday, September 18, 2013 9:46 PM
To: Postfix users
Subject: Re: Greylist Based on Error Code and 'org' Domain?

Christopher Kurtis Koeber:
> Hello,
>
> I am wondering if it is possible to greylist email systems based on:
>
> 1.       An error code (450 Helo Command Rejected: Host not Found).

This is currently not supported. It would require a DNS-based lookup table.

Instead, consider using a good DNSBL.

> 2.       If they are a 'org' domain.

I hope that is just an example, and not a serious spam blocking strategy.

/etc/postfix/main.cf:
    smtpd_mumble_restrictions =
        ...
        check_client_access hash:/etc/postfix/client_access

/etc/postfix/client_access:
     unknown    check_policy_service name-of-greylist-daemon-here

Many spambots don't have a usable client name (i.e.  the FCRDNS lookup
fails) so Postfix uses a clientname of "unknown".

        Wietse

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