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Call blocking, please...
From: Michael Dillon <michael () memra com>
Date: Mon, 6 Jan 1997 18:36:57 -0800 (PST)


Barry wants Sprint to block port 25 traffic from a Sprint customer
to his ISP.

On Mon, 6 Jan 1997, Sean Donelan wrote:

The phone company equivalent of Barry's request is call blocking, "beep,
boop, BEEP, The number you have dialed is blocked at the subscriber's
request."  A major impetus for this feature was 'the' telephone company's
desire to get out of the abuse and harrassment complaint handling business.
The subscriber doesn't have to give a reason why they want the number
blocked, they just ask the phone company to do it.  Due to the way SS7
works, the blocked announcement (usually) comes from the telephone company
at the origin's location.

BBNPlanet installs firewalls and filters for all sorts of customers
that don't want to recieve traffic from some sources.  You don't need
a court order to install a firewall to block traffic, just the customer's
request.  A traffic filter may be installed in any of several places, on
the destination customer's equipment, on the provider's equipment serving
the destination customer, at some intermediate point in the provider's
network, or in the provider's equipment serving the source customer.  It
could also be placed in the source customer's equipment, but in most of
these cases we are dealing with an uncooperative source customer.

There may be management reasons why an ISP doesn't want to fullfill a
customer's or non-customer's request to stop forwarding bits to/at them.
If you follow the rule used by the RBOC's managing the ATM NAP's, a PVC
may be terminated at the request of *either* subscriber.  Their policies
cause an occasional routing blackhole, but don't seem to have opened
PacBell or Ameritech up to a lot of legal liability.  And since the telco's
are extremely risk adverse, this is a pretty strong precedent.

Maybe I'll add a section to my internet-draft on Responsible Internet
Service Provider Guidelines.

    - An ISP may stop forwarding traffic at the request of either the
      source or destination.

        - Traffic forwarding filters should be symetrical, unless otherwise
          requested by *both* the source and destination.  This isn't exactly
          what I want to say, the intent is to prevent people from using their
          ISP as a shield while attacking a site that can't respond.  But
          most networks use asymtrical filters, e.g. anyone can FTP out, not
        in.  If you tell AOL you don't want mail from cyberpromo.com, you
          shouldn't be able to mailbomb cyberpromo.com from AOL either.

As always, a big concern is financial.  Who should pay for traffic forwarding
filters?  The prudish person who wants to keep the traffic out?  Or the
annoying person who wants to bother as many sites as possible?  So far the
net has had a policy, the person keeping the traffic out has to pay for
the firewall or cybernanny.

    - An ISP may charge the requestor a $100 processing fee (indexed to
      the CPI) to install or remove a traffic forwarding filter.  This
      makes it profitable for an ISP to become a spammer's haven.
-- 
Sean Donelan, Data Research Associates, Inc, St. Louis, MO
  Affiliation given for identification not representation


Michael Dillon                   -               Internet & ISP Consulting
Memra Software Inc.              -                  Fax: +1-604-546-3049
http://www.memra.com             -               E-mail: michael () memra com

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