[Mimedefang] Requiring FQDN in HELO

Rob MacGregor rob.macgregor at gmail.com
Wed Dec 28 13:45:25 EST 2005

On 28/12/05, Dirk the Daring <dirk at psicorps.org> wrote:
>    I've noticed a lot of SPAM does not have an FQDN in the HELO. It'll
> have just "localhost" or even omit a hostname entirely. Obviously, if
> the HELO is an IP address in square brackets, that's fine.
>    Is there any danger of rejecting "legitimate" E-Mail if I write my
> mimedefang-filter to:
>         1) Absent an IP address in square brackets, require a
>                 an alphanumeric string in the HELO
>         2) Reject a HELO where the alphanumeric string is not
>                 a FQDN (using a regex looking for at least
>                 one "." in the HELO string)

A number of MUAs, including Outlook, will AFAIK fall foul of that requirement.

                 Please keep list traffic on the list.
Rob MacGregor
      Whoever fights monsters should see to it that in the process he
        doesn't become a monster.                  Friedrich Nietzsche

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