sendmail: open-relay

Matthew Seaman m.seaman at
Mon Jan 4 13:02:59 UTC 2010

Peter Ulrich Kruppa wrote:
> Hi,
> I am running my own small mail-server, i.e. I use my desktop pc for
> sending and receiving my private mails.
> That worked quite nicely the last years. From time to time I tested my
> mail-server via's mail-relay tester. - Never got any
> positives.
> Now suddenly I receive one:
>         This is a test of third-party mail relay, generated via the
>         Network Abuse Clearinghouse at
>             Target host =
>             Test performed by <ulrich at> from
>         A well-configured mail server should NOT relay third-party
>         email.
>         Otherwise, the server is subject to abuse by vandals and
>         spammers,
>         and probable blacklisting by recipients of the unwanted
>         third-party
>         e-mail.
> Of course I had some fun trying to read sendmail's documentation. But I
> guess I need some help with this.
> I am running FreeBSD -STABLE 8.0 amd64 .
> I don't think I ever played around with sendmail's configuration. I just
> use it as came out of the box.
> Any ideas?

Plenty.  But it would help a great deal if you showed us your ${hostname}.mc.
The default sendmail config in FreeBSD isn't an open relay.  In fact,
it takes a bit of effort to make sendmail do open relay type stuff nowadays,
and there are big fat warnings in the docco (/usr/share/sendmail/cf/README)
about most of those.



Dr Matthew J Seaman MA, D.Phil.                   7 Priory Courtyard
                                                  Flat 3
PGP:     Ramsgate
                                                  Kent, CT11 9PW

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