Re: Fwd: Re: Digital Island sponsors DoS attempt?

[Valdis.Kletnieks () vt edu]

On Sun, 28 Oct 2001 21:53:24 PST, Adam McKenna <adam-nanog () flounder net>  said:
> You're assuming that the filterer is silently discarding the message and not
> bouncing it.  If a site is blocked from sending mail via MAPS or any other
> method, the receiver must send a bounce message to the sender to avoid
> breaking SMTP.
>
> Assuming the filterer is not breaking SMTP by silently discarding messages,
> Bob will receive a message saying that his message couldn't be delivered,
> with an explanation.

"550 Mail from open relay " $&{client_addr} " refused - see http://www.orbs.org/verify.php3?address="$&{client_addr}

Where $&{client_addr} is replaced with a dotted-quad IP.

You'd be amazed how many support people at ISPs can't figure that out.
Even *after* they visit the page.  I know this because I've gotten
my share of mail "I got this message, and my ISP people dont understand".

Of course, to quote Douglas Adams, that sort of ISP should be "first up against
the wall when the revolution comes" ;)

                                Valdis Kletnieks
                                Operating Systems Analyst
                                Virginia Tech