Implementing anti-abuse techniques on ISP networks....

Jon Lewis jlewis at
Wed Aug 6 23:09:15 UTC 1997

On Wed, 6 Aug 1997, Andy Pitts wrote:

> I too, am a small Internet Service Provider, and I too, don't want
> to block sites that my users may want to access.  But there seems
> to be a few domains that do nothing but generate spam.  Am I not
> providing a service to my users if I prevent them from being
> smothered with spam from those sites?

The issue is that there are ISPs that have filters such that their dialup
customers cannot talk to port 25/tcp of systems elsewhere on the net. 
Customers have to use the provider's SMTP servers.  The question is, is
this a good thing?  I don't think anyone would argue against UUNet and PSI
doing this with the * dialups or the *
would you do this on your own network? 

I've blocked 4 /16's and 12 /24's from talking
directly to FDT's mail servers.  Unfortunately, most of the junk from PSI
is relayed through other sites anyway.
 Jon Lewis <jlewis at>  |  Unsolicited commercial e-mail will
 Network Administrator       |  be proof-read for $199/message.
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