First, the correct slang term for unsolicited bulk email is "spam", never "SPAM". The latter is a product of the Hormel Corporation and has nothing to do with email; the former is not an acronym and thus should never be rendered in all-caps. On Thu, Oct 22, 2015 at 06:41:54PM +0200, JORDI PALET MARTINEZ wrote: > 1) IETF is accepting messages from subscribers with MX which are Blacklisted. Second, blacklisted by *whom*? There are hundreds of public blacklists and no doubt several orders of magnitude more private ones. Some of these list enormous swaths of network space. I wouldn't be surprised if *most* of the messages accepted by IETF mail servers originate from hosts that are in some blacklist, somewhere. (Also, I don't think you mean their MX's, necessarily. You mean their outbound mail servers, which may or may not be the same as the hosts listed in their MX records.) > 3) Mail servers inspect the IETF and original headers looking for > black-listed servers. > > 4) If they are strict, bounce emails from IETF even if the IETF records > aren???t black-listed but the original sender MX is black-listed Third, there's your problem. Don't do that. If you subscribe to a mailing list, IETF or otherwise, you should accept all traffic from that mailing list. It's up to the keepers of the mailing list to keep it from of spam, which these days isn't all that hard modulo the occasional compromised list-member account. And it's up to you to accept all messages from the mailing list *because you subscribed to it*. If you don't want to cede authority over list traffic decision-making to the keepers-of-the-list, then don't subscribe to it. ---rsk