Re: vger rejecting messages from mediaone (ORBS is evil)

From: Matti Aarnio (matti.aarnio@sonera.fi)
Date: Tue Jan 18 2000 - 11:18:40 EST


On Tue, Jan 18, 2000 at 08:38:07AM -0500, Mike Porter wrote:
> Most likely the problem is above.net has customers who can't
> upgrade to a newer mailer that can block relaying.

        So put such a system behind a ``firewall'' (which does not
        necessarily mean expensive things, perhaps just IP ACL at
        the network egress router) and divert all incoming email to
        do so via a bastion server by means of MX records. Trivial.

        If you don't want to construct such bastion yourself, ask
        your ISP to act as such, and do router ACL blocking to
        limit incoming SMTP connectivity from your ISP's server
        network.

                http://www.zmailer.org/smtprelay.html

        If the receiving server is vulnerable to things like:
                <"foo@somewhere.com"@receiver.com>
        these ISP bastions don't help, as ISP can't analyze
        that the address in the local part is a cocoos egg..
        (Same *may* also harm self-kept fw/bastions.)

> Mike

/Matti Aarnio

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