The below is a belated summary of the the discussion of spamming on the lir-wg list soon after RIPE 28. I'm copying it to John Martin of TERENA as input to the BoF he is kindly organising during RIPE 29 later this month. Regards and happy new year. Mike Norris There was broad consensus that: - spammers can be clever and operate professionally - they can forge e-mail, IP addresses, even routes - they constitute at least a nuisance to users - they use inordinate levels of network and CPU resource without any charge - in some cases, the volume of traffic they generate impacts seriously on the performance of a network There were many calls for concerted action, for ISPs to back each other up, even for RIPE to take legal action against spammers. When it came to specifics, there were some points of good practice which were generally accepted and from which all could benefit. These included: - filter inbound routes on AS (lest spammers inject false routes and mail from the corresponding IP addresses) - configure sendmail to do relay only for specified hosts (to prevent spammers from using your mail server as a relay for spamming) - no-relay patches on http://www.sendmail.org/ - use sendmail patches to check From and To addresses - tighten up rules (and enforce them) for domain registration/de-registration - implement and enforce AUP and peering agreements - make address harvesting difficult e.g. www.e-scrub.com/wpoison Other anti-spamming defences, from the point of view of the recipient, included: - a daemon that checks the incoming mail queue for certain patterns of use, domains, volume of messages, etc. If a spam is detected, the daemon blocks reception of packets from the address/domain originating the spam for about 15 minutes. After that the reception is restored. - blocking SMTP access to bogus domains and addresses (not just CyberPromo) - accept the spam mail and don't deliver it On the supply side, too, ISPs suggested a range of measures to thwart spammers in their efforts to send bulk e-mail. - charge per item for delivery of e-mail with advertising material in it - regulate the number of RCPTs from a given MAIL FROM value (but how to authenticate the MAIL FROM value used?) - force dialup customers to use their ISPs SMTP relay, validate MAIL FROM value, check for forged headers, check sender identity There were those too who said that selective filtering, route denial and other practices by ISPs were not the way to go. Just because these were technically possible did not mean they had to be used; to do so could set a dangerous precedent which could be invoked in the future by outside agencies set on "controlling" the Internet. Rather, the users should be enabled to do their own filtering and many providers are equipping them with the means to do so. It is difficult, having seen the range of opinions expressed, to see a consensus about concerted action involving intervention in the mail transport mechanism, even in the European region. of spammers and dynamically blocking their routes, both of which are technically possible and already implemented in places. On balance however, it seems that the considered view is on the side of "freedom of speech". Whatever, people felt that European ISPs should act in concert and should adopt a common set of technical and administrative anti-spam measures. These would start with those listed above and might also include: - Set up a mailing list for LIR postmasters - Use digital signatures, with trusted SMTP servers - For dialup access, use TACACS+ Legal action, too, had its proponents and opponents. Instances of courts in Europe and USA finding against spammers were given, and used to suggest that RIPE might even take up legal cudgels against spammers and on behalf of its clients. As against this, there is the argument that the industry should be self-regulated, and that it should protect itself against itself. RIPE and the NCC have successfully adopted this approach to deal with IP address registration and other activities in Europe. Contributors to the discussion were: James Aldridge Sebastian Andersson Peppino Anselmi Alex Bligh Adrian Bool Pedro Ramalho Carlos Mickey Coggins Edgar Danielyan Jorgen Ericsson Ina Faye-Lund Clive D.W. Feather Kevin Ferguson Michael Ferioli gert@Space.Net Geert Jan de Groot Stephan Hermann Nick Hilliard Keith C. Howell Miroslaw Jaworski Poul-Henning Kamp Daniel Karrenberg Mihkel Kraav Andres Kroonmaa Simon Leinen Maarten E. Linthorst Javier Llopis Neil J. McRae Andre Oppermann Chris Panayis Morten Reistad Matt Ryan Luis Miguel Sequeira Paul Thornton Mario Valente Espen Vestre Francois Weil Toby Williams