Re: How do I find the source of the spammers?
Paul Wade wrote:
>
> The problem of "relaying" can be solved by restricting access to the local
> subnet. However, that would irritate some good customers. Suppose I am
> traveling with my laptop and want to read and answer my email. I don't
> want to pay for a toll call to the dialup because I can hook up via
> ethernet or my brother says 'go ahead and use my local dialup account'.
Well, I don't see it as an irritation. I do travel with my laptop and
I do get/send email while on the road. But if you're on the road
and have access to the internet but not through your own ISP, you
*should* have access to the sendmail server for whoever's Internet
hookup you're using. I find it quite painless to simply go into my
Netscape Mail settings and set the outgoing mail server to whatever
the "local" sendmail server is. As long as your "Reply-To:" header
is set correctly, you'll have not trouble getting replies sent through
a "foreign" sendmail server.
And besides, are you saying that *your* sendmail will accept connections
from the outside world? You are truly a brave spirit, given the seeming
never-ending source security holes which sendmail has always been.
> There is a way to fix this for the ISP who thinks it's worth the trouble.
> You could set up a web page that requires a password or have them login
> via telnet. This would validate the IP the customer is at and you could
> allow in.smtp because you know who to 'counsel' if you get a spam
> complaint.
>
> I suppose that you could require the telnet connect to stay active in
> order to accept mail for relaying. They would have to switch to the telnet
> and hit a key within n(60?) seconds before sending or the connect to smtp
> would be refused. Hopping between open telnet and mailer programs is easy
> for Windows or Linux users.
>
> The apache approach has several possibilities. Maybe a javascript (ugh)
> would be sufficient to tell the server you are still valid from the IP.
>
> If somebody does this, they should share it freely. Most of the spam comes
> from 'borrowed' mail servers.
I think the ultimate solution is to build support into mail clients
for ssh or something of the like.
--
Jens B. Jorgensen
jjorgens@bdsinc.com
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