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Re: blocking dialups

  • From: Richard Kettlewell < >
  • Date: Thu, 15 Oct 98 10:16:29 +0100 (BST)

Clive D.W. Feather writes:

> Who is "us" ? The point is, I can't afford to have those emails sent
> via the ISP's relay, because then the sender's IP address will be
> wrong.

That needn't be a problem.  If a firewall can fake things up from the
client's point of view (and I've seen this done, albeit badly) then it
can make the TCP connection appear to the server to come from the
client too.  From the IP addresses, the client and server would
believe they were talking to each other, when in fact they'd both be
talking to some process on the firewall.

That process can then do whatever rate-limiting or spam-detecting it
does, and clamp down when it detects a spammer (as defined by local
policy).

ttfn/rjk




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