Spam Control Considered Harmful

Paul Peterson paulp at
Thu Oct 30 09:27:06 UTC 1997

Im not sure of your logic about disabling the "invalid"
filtering from your sendmail. I wouldn't do it for just one of my
customers and expose the rest of my customers to spammers that
intentionally try to hide themselves by faking a return address and/or
masking their relay server with a bogus name. I would tell that one
customer to have their constituent with no reverse DNS to get there
setup corrected because:

a. It is a proper and complete DNS config to have reverse mapping to
your ip
b. It makes all data originating from it accountable (not just spam but
smurf attacks, DOS attacks, port scans/Satans etc.)
to the organization/person responsible for the forward and reverse zone
(if they match)
c. It gives other ISP's and businesses the choice to filter or not
filter. If one of us makes policy to make exceptions for a customer,
then they tell other customers who tell other customers who tell other
potential customers that an ISP should not filter e-mail on this

Let the 1 in 5 people in the Internet who are either lamers who don't
know how to do reverse DNS properly or too lazy to do it keep their
problems as their problems and not ours. Already there are a ton of TCP
wrapper applications, FTP sites, telnet sites, Netscape U.S. Encryption
pages for Navigator, etc that will not allow access with improper or
non-existant reverse DNS entries. Would you consider not doing
gethostbynames on your entire web server because one of your web clients
wanted their mis-configured customers elsewhere in the internet to have
that much faster access on web pages which would also give the rest of
your customers stat pages full of IP's only ?? I wouldn't......

None of my customers have complained about us filtering the
misconfigured people. 80% of my customers are business who
exchange a lot of mail with other businesses on the net, maybe they
don't care ? I dunno.

As for responsible service providers disconnecting abusers, we have
disconnected around 10 of them so far. I guess wer'e luck we haven't ran
into a Spamford Wallace yet huh ?

Just my opinion, thanks for tolerating it.

Paul Peterson, WinterLAN Inc.

> -----Original Message-----
> From:	Jon Lewis [SMTP:jlewis at]
> Sent:	Wednesday, October 29, 1997 9:25 PM
> To:	Cal_Thixton at TPA.Net
> Cc:	Phil Lawlor; nanog at
> Subject:	Re: Spam Control Considered Harmful
> On Wed, 29 Oct 1997, Cal Thixton - President - ThoughtPort Authority
> of Chicago wrote:
> > 	I personally see no practical technical means of eliminating the
> > practise of spamming and rather than spending time trying to dream
> up
> > fancier and smarter sendmail's, we should seek to simply expand the
> > current mail fraud laws to cover electronic mail.  Then we can
> simply
> > sic the FBI on these people armed with terabytes of logs and spam
> emails
> And what will the FBI do when spammers leave the US and do their deed
> from
> other countries?  Spammers won't be stopped by legislation or
> technology...the average internet user can't handle the amount of
> technology necessary to keep spam out of their mail.  The average
> sysadmin
> isn't much better off.  I had to disable my latest anti-spam sendmail
> rule
> today (denying incoming mail from sites with no or incorrect
> DNS) because a client is trying to do business with a site that has
> existed for a year an a half and never setup DNS.
> Spam can only be stopped by responsible providers not allowing their
> clients to abuse the net.  Phil's attitude of "We provide internet
> connectivity.  If you don't like spam, _you_ do something about it."
> has
> nearly destroyed AGIS.  Who's going to be next?
> BTW...Cal...obtain a linefeed.
> ------------------------------------------------------------------
>  Jon Lewis <jlewis at>  |  Unsolicited commercial e-mail will
>  Network Administrator       |  be proof-read for $199/message.
>  Florida Digital Turnpike    |  
> ______ for PGP public key____

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