Spaming relaying and Port 25 Blocking

Jeremy Porter jerry at
Tue Dec 22 21:29:46 UTC 1998

Has anyone got any operational experience with blocking Port 25 from
dialup blocks or instituting a "transparent" proxy system that limits
email volume?  I will summarize and respect privacy requests regarding
information.  This looks to be fairly straightfoward to do with
NAT/"L4 switch" (I hate that term), such as a Alteon or Foundry.

I would like to have something like this in operation by end of Q1 99,
but want to minimize or eliminate customer pain.  This way anyone
running proxies on downstream sites, or dialup farms, would have not
excuse to not prevent dialup accounts from sending to relays.

Those of you in my .procmailrc need not reply, as I won't see it anyway,
as we are completely aware of the legal issues involved and know what
we are doing.

Jeremy Porter, Freeside Communications, Inc.      jerry at
PO BOX 80315 Austin, Tx 78708  |  512-458-9810

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