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Date:      Thu, 01 Jul 1999 12:41:44 +0100
From:      Jason Thomson <jason.thomson@mintel.co.uk>
To:        freebsd-isp@freebsd.org
Subject:   Sendmail 8.9.x check_mail anti-spam rule broken?
Message-ID:  <377B53F8.34DE5461@mintel.co.uk>

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As I understood the sendmail anti-spam rules,  they are supposed to reject
Sender addresses whose domain part does not _resolve_.  I was under the
impression that meant the domain had to have either MX or A or CNAME
records.

However,  it would appear that the domain must have an A record.  Or mail is
rejected with:

    reject=451 <>... Sender domain must resolve


For example,   some.one@btinternet.com gets rejected.  But btinternet.com
has perfectly valid MX records.  BT Internet is probably one of the UK's
biggest ISPs.

Can someone confirm that this is the expected behaviour (and I haven't got a
broken config) and that this behaviour is correct (and not a bug).

If by _resolve_,  this means that a domain must have an A record,  then
maybe I need to add A records for all the domains that I maintain,  and
remove this anti-spam rule from my sendmail.cf file.  (Because I might want
to be able to receive mail from companies like British Telecom,  MCI
Worldcom etc. :-).

However,  this it doesn't seem quite right that a domain should require an A
record.  (I notice that freebsd.org does have an A record).  Also,  whilst
our server rejected one legitimate message,  that same rule has rejected
several spams already today.

Thanks for any pointers and info.



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