> Another example:
> Received: from proping (NK218-187-59-152.4-174.pl.apol.com.tw
> [218.187.59.152])
>         by reva.sixgirls.org (8.11.6/8.11.6) with SMTP id gA3H08d24914
> 
> Well, proping doesn't resolve to anything, so I'd like my mail server to
> reject this.

No, you can't do that.  You lose all mail that comes out of systems
with dynamic addresses, and (probably) those with multiple interfaces.

In any case all you then do is add the feature to sendmail to make
it do a dns lookup for its own address so that it can put its
external name into the helo= message.

	David

-- 
David Laight: david@l8s.co.uk