| From: Alvin Starr via talk <talk@gtalug.org> | SPF should insure that only your email servers can be used to send mail from | your domain. Related: My Postfix server validates HELO / EHLO records. These records declare the name of the server contacting my server. Postfix makes sure that the declared name resolves to the IP address from which the server was contacted. At least that's what I think it does.
From /etc/postfix/main.cf:
smtpd_helo_restrictions = permit_mynetworks, reject_invalid_helo_hostname, reject_non_fqdn_helo_hostname, reject_unknown_helo_hostname This catches a lot of SPAM. But it also blocks a few badly configured servers that I want to get messages from. The ones that I've noticed: - some parts of Sunnybrook hospital - rakuten I have been unable to contact the technical people at these sites to get them to fix their problem. | There was once a guy who insisted on running an open relay and believed that | anybody blocking open relays were infringing on his rights. | He was VERY loud about his convictions that open relays were not the problem, | spammers were. John Gilmore? He's generally soft-spoken but has strong convictions. <https://en.wikipedia.org/wiki/John_Gilmore_(activist)> Hugh Daniel? Sadly gone. But he definitely was loud. <https://en.wikipedia.org/wiki/Hugh_Daniel> BTW, both are/were strong forces for good.