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A comment on Show HN: I made an open-source anonymous email forwarding service. Parent comment

Re:Show HN: I made an open-source anonymous email forwarding... by bardan on Wednesday November 27, 2019 @10:07PM (#21654314)
My mail server got blacklisted because of backscatter. That is where the sender sends spam to an address that doesn't exist on your server, but they also forge the "from" address, so the "this message could not be delivered" response, complete with the spam message, is sent "back" to the forged address (the spammers real target)

It took several months or a large payment to the people maintaining the blacklist for my server to get unblocked (it wasnt critical so I didnt pay). Seemed like extortion to me, but Google and others respected this particular blacklist.

Im not sure if this list still exists. It was on the blacklist checking websites at the time

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Re:Show HN: I made an open-source anonymous email forwarding... by 55555 on Wednesday November 27, 2019 @10:27PM (#21654383)
Which blacklist was it and how much did they charge? I have always wondered which are more mafia-esque and which less, as they all act so innocent but are also so adamant about hiding their pricing.
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Re:Show HN: I made an open-source anonymous email forwarding... by bardan on Thursday November 28, 2019 @07:02PM (#21660985)
It was backscatterer.org. I seem to recall it was in the low hundreds, but it was quite a while ago now.
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Re:Show HN: I made an open-source anonymous email forwarding... by LIV2 on Thursday November 28, 2019 @01:39AM (#21655101)
I'm guessing backscatterer.org

The fix is to configure your MTA so that it doesn't send backscatter

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Re:Show HN: I made an open-source anonymous email forwarding... by bardan on Thursday November 28, 2019 @06:59PM (#21660969)
It was backscatterer.org. I don't recall how simple the fix was, but I couldn't find much information on it at the time. The list appeared last in the blacklist tools so I figured it was a fairly new thing.
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Re:Show HN: I made an open-source anonymous email forwarding... by cx42net on Friday November 29, 2019 @03:04AM (#21662870)
How can you know when you're about to send a bounce to a backscatter? I'd love to know this!
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Re:Show HN: I made an open-source anonymous email forwarding... by LIV2 on Wednesday December 04, 2019 @12:58PM (#21704834)
Sorry for the extremely late reply, but you can test using http://its-netzwerk.com/bscatter/

Alternatively attempt to send a message to a nonexistent address on your MTA using telnet which should throw an error after "RCPT TO" if the server is configured correctly Steps to test SMTP via telnet: https://my.esecuredata.com/index.php?/knowledgebase/article/...

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Re:Show HN: I made an open-source anonymous email forwarding... by cx42net on Wednesday December 04, 2019 @03:25PM (#21706517)
Thank you for your reply. From my understanding, what you suggest is that a backscatter uses a return path email that does not exists?

My understanding was that a backscatter uses an email that is not his, in order to deliver a message without sending it directly (and making the bounce server act like a spammer).

Am I missing something?

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Re:Show HN: I made an open-source anonymous email forwarding... by willbrowning on Thursday December 05, 2019 @08:06AM (#21711946)
Here is a good blog post [1] that explains backscatter and some ways to help prevent it.

[1] https://willem.com/blog/2019-09-10_fighting-backscatter-spam...

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Re:Show HN: I made an open-source anonymous email forwarding... by cx42net on Monday December 09, 2019 @10:42AM (#21743525)
Thanks!
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