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