Hello,

Does anyone know how to configure Sendmail to compare a connecting
server's (claimed) hostname and the IP address of that server? As an
example:

    [216.27.131.62])
        by reva.sixgirls.org (8.11.6/8.11.6) with ESMTP id g9E3ct610763

Now I know that durga.theundergroundcity.com is not the same as
durga.indira.net, but I don't care about that. I just want to see if the
name the server calls itself (durga.theundergroundcity.com) resolves to
the same IP address as this server. In this case, it does, so I'd want to
accept this.

Another example:
[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.

Another:
[217.96.138.143]) by    email.softwarevisual.com with SMTP (Microsoft Exchange Internet Mail
Service Version 5.5.2653.13)

mail.interac.it resolves to 212.183.164.3, which doesn't match
217.96.138.143. Drop.

I am just amazed at how many SPAM claim to come from something.hotmail.com
or something.yahoo.com, and I'd love to block them using this very simple
method.

Thanks,
John Klos
Sixgirls Computing Labs