Re: [GTALUG] lazy jail server admin forced to act

On 2024-01-08 05:22, ac via talk wrote: [snip]
https://ascams.com/info/domain-anti-forgery/
https://www.rfc-editor.org/rfc/rfc7208.txt
imnsho you can add dkim etc - but ALL Cyber Criminals have DKIM & DMARC in fact ALL SPAMMERS also have DKIM & DMARC so it is a fairly useless thing/loop to jump through and disables privacy and has more minusses than plusses for general society.
anyway, ymmv
Andre
SPF and DKIM are more to make it harder for people to spoof your email address. SPF should insure that only your email servers can be used to send mail from your domain. DKIM has the advantage of digitally signing your emails as they go out so that if someone screws with them it should be obvious. DMARC is more about information sharing so that you can get and give reports about who is trying to spoof email. This does not help with spammers who are using Microsft, or Google so that the email comes from their domains. But at least you can stop people sending stuff out as though it was coming from your domain. 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. Granted, closing down open relays did not make spamming go away. It did cut down on the vectors that spammers could use to get their content out. -- Alvin Starr || land: (647)478-6285 Netvel Inc. || Cell: (416)806-0133 alvin@netvel.net ||

| 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.
participants (2)
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Alvin Starr
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D. Hugh Redelmeier