RBL check combines SMTP sender and Mail_From domains

Vernon Schryver vjs@calcite.rhyolite.com
Sun Sep 14 02:54:15 UTC 2008

> From: Gary Mills <mills@cc.umanitoba.ca>

> ...
> The problem was that the SMTP peer's IP address,, was
> not on a zen blacklist.  It was actually their e-mail domain name that
> resolved to that was on the blacklist.  The error is
> certainly confusing.  The MX record for that domain was not on the
> blacklist.  Likely their e-mail domain is also their web site, making
> it difficult for them to change.

Is the "e-mail domain name" what is later called the "e-mail sender domain"?
It may sound picky to ask, but all of the domain names in the SMTP HELO
command, SMTP envelope Mail_From command, Rcpt_To command(s), and even
various SMTP headers including From:, To:, Repy-To:, Sender:, Received:
and Cc: might be called "e-mail domain names."

> For now, I'd like to have dccm check only the SMTP peer, not also the
> e-mail sender domain.  Is this possible somehow, perhaps in a newer
> version?  I'd also like to have the actual IP address that failed an
> RBL lookup listed on the SMTP rejection error line.  Is this possible?

What is meant by "e-mail sender domain"?  If it is the domain name
in the SMTP envelope Mail_From command, then perhaps this text from
the announcement of version 1.3.92 in
is relevant

    Replace -Bno-envelope for dccm, dccproc, and dccifd with
        -Bno-client and -Bno-mail_host for Tony Del Porto.  It seems that
        Spamhaus' PBL should generally not be applied to SMTP envelope
        Mail_From domain names to avoid rejecting mail received through an
        ISP smart-host but with sender domain name hosted on a dynamically
        assigned IP address.  The now undocumented -Bno-envelope implies
        -Bno-client and -Bno-mail_host.

Vernon Schryver    vjs@rhyolite.com

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